如果您使用Mac，您可以将PDF(PDFs)与仅适用于 macOS的内置预览应用程序结合起来。(Preview)它快速、安全且直接。我们将向您展示如何。
在Mac上合并PDF(PDFs)可以更轻松地阅读、共享和打印文档，并减少文件混乱。为了让事情变得更好，您不必下载第三方应用程序或依赖基于 Web 的工具。在 macOS 中合并PDF(PDFs)所需的只是 Apple 的原生Preview应用程序。
如何在 macOS 中使用预览(Preview Works)合并 PDF(Merging PDFs)
在Mac上，您可以使用Preview快速合并两个或多个 PDF 文件。只需打开一个文件，然后按照您希望的方式插入其他文档即可。
预览还允许您对文件中的页面重新排序，甚至可以在将所有内容导出到单个(Preview)PDF之前或之后删除任何您不想要的内容。该应用程序甚至允许将文档中的单个页面与另一个文件合并。
但是，在开始之前，请记住预览(Preview)会自动保存对您打开的第一个PDF文件的所有更改。Edit > Revert到 > 上次打开
来避免这种情况。
或者，您可以打开系统(System) 偏好设置(Preferences)，选择常规(General)，然后取消选中关闭文档时要求保留更改旁边的复选框。默认情况下，这将阻止Preview（包括 Pages 和 Numbers 等其他股票应用程序）保存更改。
合并两个或多个 PDF
按照以下步骤将macOS 中的PDF(PDFs)与Preview结合起来。您可以合并任意数量的文档。
1. 双击第一个PDF以在(PDF)Preview中打开它。如果它启动不同的应用程序，请按住 Control 键单击(Control-click)或右键单击并选择打开(Open)方式> Preview。
2. 选择预览(Preview)窗口左上角的选择侧边栏显示按钮，然后选择(Choose)缩略图(Thumbnails)。
或者，在菜单栏上选择View > Thumbnails这应该会在左侧边栏中以缩略图格式显示PDF页面。
3.向下滚动(Scroll)侧边栏并选择最后一页缩略图。
注意：如果您希望以下PDF出现在第一个文档中的特定页面之后，请选择相关的缩略图。或者，您可以稍后重新组织所有内容（下一节将详细介绍）。
4.在菜单栏上Select Insert > Page文件中的页面。如果您希望在PDF(PDF)文件之间出现空白页，请在执行此操作之前选择空白(Blank)页选项。
5.在Finder窗口中选择第二个PDF并选择(PDF)Open。
6. PDF将出现在第一个文件（或您选择的任何其他页面）的最后一页之后。使用侧边栏确认。(Confirm)如果要添加更多文档，请
重复步骤 3-5。(Repeat)
7.Select File > Export（或按住Option键并选择另存为(Save As)）。
8. 将合并后的PDF文件保存到(PDF)Mac上您想要的位置。
或者，使用格式(Format)下拉菜单，您可以将PDF保存为图像文件（JPG、PNG、HEIC等）。您还可以选择权限(Permissions)按钮以密码保护和限制对PDF的更改。
如果您想回滚对原始PDF的更改，请不要忘记在关闭PDF之前选择(PDF)Edit > Revert到 > 上次打开。如果您已将Preview配置为默认不保存更改，请退出Preview并选择Revert Changes。
合并前
重新排序和编辑页面(Edit Pages)
在导出合并的PDF文档之前，您可以使用“预览(Preview)”对页面重新排序或删除任何您不想要的页面。或者，您可以打开文档并稍后进行更改。
重新排序页面
只需按照您希望它们出现的顺序将页面缩略图向上或向下拖动预览侧边栏。(Preview)要同时移动多个页面，请按住Command键，进行选择，然后一次将它们全部拖动。
删除页面
选择侧边栏上的页面缩略图，然后按Delete键。如果您想删除多个页面，请按住Command键，做出选择，然后按下Delete键。
除了上述内容之外，Preview还可以让您对(Preview)PDF(PDFs)进行注释并执行许多其他操作。查看所有这些在 Mac 上使用 Preview 的不同方式(different ways to use Preview on your Mac)。
(Merge Specific Pages From)合并另一个PDF中的特定页面
您还可以使用预览将(Preview)PDF中的特定页面与另一个文档合并。要做到这一点：
1.在单独的预览(Preview)窗口
中打开PDF 。(PDFs)
2. 显示两个PDF(PDFs)的侧边栏。
3. 调整两个预览(Preview)窗口的大小以使其可见或启动拆分视图(initiate Split-View)。
4. 拖动要包含在其他PDF中的文件的页面缩略图，并将其放到您希望它出现在侧边栏上的位置。例如，如果您希望文档的第 4 页出现在另一个文件的第 2 页和第 3 页之间，只需将其拖放到这些缩略图之间即可。
如果要同时移动多个页面，请按住命令(Command)按钮，进行选择，然后一次将它们全部拖动。
7.Select File > Export并保存新的PDF。
Mac的第三方推荐
尽管有Preview，第三方工具仍然可以使合并更加容易，尤其是当您有许多PDF 文件(PDFs)要合并时。这里有几个第三方选项，您也可以使用它们在Mac上合并(Mac)PDF文件。
无可争议的PDF 编辑器(PDF editors)之王Adobe Acrobat可让您使用其组合(Combine)工具合并PDF 。(PDFs)您可以添加PDF(PDFs)，以任意顺序拖动它们，并在将所有内容保存为单个文档之前重新排列页面。只要您在Adobe创建一个免费帐户，您就可以通过(Adobe)使用 PDF 编辑套件的在线版本(using the online version of the PDF editing suite)来避免支付高额订阅费用。
PDFsam Basic是一个免费的PDF实用程序，它提供了以您想要的任何顺序合并PDF所需的所有要素。(PDFs)您可以在合并过程中从每个文件中省略不需要的页面。但是，它不允许您编辑PDF(PDFs)。
在线PDF(PDF Online)
PDF Online是一个免费的在线工具，可让您在合并之前对PDF进行排序和重新排序页面。(PDFs)但是，我们建议在合并包含敏感或机密信息的文件时避免使用在线工具。
iPhone 和 iPad 怎么样？
如果您还使用 iPhone 和 iPad，iOS 和 iPadOS 中内置的文件应用程序可以让合并(Files)PDF文件变得非常容易。只需(Just)选择您希望它们显示的文件，然后点击“文件”(Files)应用程序窗口底部的“组合”按钮。(Combine)这就是它的全部！
How to Merge PDFs in macOS with Preview
If you use a Mac, уou can combine PDFs with just the built-in Preview app for macOЅ. It’s quick, ѕafe, and strаightforward. We will show you how.
Merging PDFs on the Mac makes it easier to read, share, and print documents and reduces file clutter. To make matters better, you don’t have to download third-party apps or rely on web-based tools. All you need to combine PDFs in macOS is Apple’s native Preview app.
How Merging PDFs in macOS With Preview Works
On the Mac, you can use Preview to combine two or more PDF files quickly. It’s just a matter of opening a file and then inserting other documents as you want them to appear.
Preview also lets you reorder pages within files and even delete any you don’t want before or after exporting everything into a single PDF. The app even allows merging individual pages from a document with another file.
However, before you start, remember that Preview auto-saves all changes to the first PDF file you open. You can avoid that by selecting Edit > Revert To > Last Opened on Mac’s menu bar before closing the file.
Or, you can open System Preferences, select General, and uncheck the box next to Ask to keep changes when closing documents. That will stop Preview (including other stock apps such as Pages and Numbers) from saving changes by default.
Merge Two or More PDFs
Work through the following steps to combine PDFs in macOS with Preview. You can merge as many documents as you want.
1. Double-click the first PDF to open it in Preview. If it launches a different app, Control-click or right-click and select Open With > Preview.
2. Select the Choose sidebar display button at the top-left corner of the Preview window and select Thumbnails.
Or, choose View > Thumbnails on the menu bar. That should reveal the PDF pages in thumbnail format along the left sidebar.
3. Scroll down the sidebar and select the final page thumbnail.
Note: If you want the following PDF to appear after a specific page within the first document, select the relevant thumbnail instead. Or, you can re-organize everything later (more on that in the next section).
4. Select Insert > Page from file on the menu bar. If you want a blank page to appear between the PDF files, select the Blank page option before you do that.
5. Select the second PDF on the Finder window and choose Open.
6. The PDF will appear after the last page of the first file (or any other page you selected). Confirm using the sidebar. Repeat steps 3–5 if you want to add more documents.
7. Select File > Export (or hold down the Option key and select Save As).
8. Save the combined PDF files to the location you want on your Mac.
Alternatively, using the Format drop-down menu, you can save the PDF as an image file (JPG, PNG, HEIC, etc.). You can also select the Permissions button to password-protect and restrict changes to the PDF.
If you want to roll back the changes to the original PDF, don’t forget to select Edit > Revert to > Last Opened before closing the PDF. If you’ve configured Preview not to save changes by default, quit Preview and select Revert Changes.
Re-order and Edit Pages Before Merging
Before exporting a combined PDF document, you can use Preview to reorder pages or delete any you don’t want. Or, you can open the document and make the changes later.
Reorder Pages
Just drag the page thumbnails up or down the Preview sidebar in the order you want them to appear. To move multiple pages simultaneously, hold down the Command key, make your selections, and drag them all at once.
Delete Pages
Select the page thumbnail on the sidebar and press the Delete key. If you want to delete multiple pages, hold down the Command key, make your selections, and press Delete.
In addition to the above, Preview lets you annotate PDFs and do many other things. Check out all of these different ways to use Preview on your Mac.
Merge Specific Pages From Another PDF
You can also merge specific pages from a PDF with another document using Preview. To do that:
1. Open the PDFs in separate Preview windows.
2. Reveal the sidebars on both PDFs.
3. Resize the two Preview windows to make both visible or initiate Split-View.
4. Drag the page thumbnail of a file you want to include within the other PDF and drop it where you want it to appear on its sidebar. For example, if you want page 4 of a document to appear between pages 2 and 3 of the other file, just drag and drop it between those thumbnails.
If you want to move multiple pages simultaneously, hold down the Command button, make your selections, and drag them all at once.
7. Select File > Export and save the new PDF.
Third-Party Recommendations for the Mac
Despite having Preview, third-party tools can still make merging even easier, especially when you’ve got many PDFs to combine. Here are several third-party options you can also use to merge PDF files on the Mac.
The undisputed king of PDF editors, Adobe Acrobat, lets you merge PDFs with its Combine tool. You can add PDFs, drag them around in any order, and rearrange pages before saving everything as a single document. You can avoid paying for a hefty subscription by using the online version of the PDF editing suite so long as you create a free account with Adobe.
PDFsam Basic is a free PDF utility that provides all the essentials you need to merge PDFs in any order you want. You can omit unwanted pages from each file during the merge process. However, it does not allow you to edit PDFs.
PDF Online is a free online tool that lets you sort PDFs and reorder pages before combining. However, we recommend avoiding online tools while merging files containing sensitive or confidential information.
What About the iPhone and iPad?
If you also use an iPhone and iPad, the Files app built into iOS and iPadOS makes it ridiculously easy to merge PDF files. Just select the files as you want them to appear and tap the Combine button at the bottom of the Files app window. That’s all there’s to it!
