Check out or check in files in a document library - Microsoft Support

Learn how check files, folders, and links out of your SharePoint document library, and check them back in or discard a check out.

Sharepoint Library Require Check Out feature and OneDrive Sync

Is there a way in the new SharePoint to check in multiple

Allow people to see who views their files or pages - Microsoft Support

Use the Document Library web part - Microsoft Support

The basics of SharePoint check in and check out

How to Check out a file in SharePoint Online - Microsoft Office

Check out or check in files in a document library - Microsoft Support

File activity in a document library - Microsoft Support

How to Access Checked-Out Files - SharePoint Document Checkout