On the Info tab, you can:
Protect a file from changes
Inspect a file for various kinds of problems or information
Manage previously saved versions of a file
View document properties such as size, pages, last modified date, and more
Select Browser View options (in Excel)
Compress audio and video (in PowerPoint)
Additionally, if you're an enterprise customer and your file is stored on SharePoint or OneDrive for Business, you may see a chart that shows you how many views your document has had, when, and by whom, as well as suggestions for others in your organization you may want to consider sharing the file with.
Basic File Information
At the top you'll see the name of the file, along with the path where the file is stored. Beneath that you'll find handy buttons to let you open the file location in Windows File Explorer or share the file. Depending on where the file is shared you may also see buttons that enable you to upload the file to the cloud, or copy the file path (where the file is stored) to the clipboard so you can paste it elsewhere.
On the right side of the Info screen you'll find document properties that tell you about the file. How large it is, when (and by whom) it was last edited, total editing time, and more. For more information about these properties see: View or change the properties for an Office file.
In Office, you can use a password to help prevent other people from opening or modifying your file. You can also use "document protection" to restrict the types of changes that reviewers can make.
See Add or remove a digital signature in Office files if you need to assign an electronic stamp of authentication to a file.
See Help prevent changes to a final version of a file to notify others that a file shouldn't be edited any more.
Office can inspect your document for personal information that you don't want to share. It can also inspect for revision tracking data, for accessibility problems, or for compatibility with older versions of Office.
Manage gives you options for working with versions of your file. You can view, and restore previous versions of your file if you want to see, or undo, changes.
Additionally you may be able to recover unsaved versions of your file if Office crashed before you were able to save your latest edits.
If your file is stored on SharePoint, or OneDrive for Business, you can also check out your file which creates a local, private, copy and blocks others from making changes to the file. When you're finished return to the Info tab to check it back in.
Select Browser View options
For Excel workbooks stored on OneDrive, OneDrive for Business or SharePoint Online, you can define which parts of the file are visible to folks who open it in a web browser (Excel Online).
See Use Browser View Options for more information.
In PowerPoint, if you have audio or video in your presentation, Compress Media appears on the Info tab. It helps you compress the media, which can improve playback performance and save disk space.
See Compress your media files for more information.