When bulk editing content, columns can be remapped with different columns in the same list, even if they have a different field type.
Prerequisites
- You have site collection admin permissions on your targeted site collection.
- You have term store admin permissions on your source and destination if you have managed metadata (Terms, Term sets, Term set groups) in your editing scope.
- You are connected to your site collection, Microsoft 365 Admin center, or SharePoint central admin.
Note: Site collection admin permissions are required even if you have higher admin privileges like SharePoint admin or Global admin permissions. For more information click here.
Index
How-To
- Click Explorer.
- Select a site.
- Click Bulk edit content from the Quick actions menu at the right.
- Select the list or library you would like to bulk edit.
- Click Mappings in the top right corner.
- Select the Properties tab.
- When you are done mapping, click on Save or Export
your mappings to Excel. You can also Import 
a mapping file and Restore Default Mappings. - Click on Next.
- Click Bulk Edit.
Note: You can't add fields to your lists or libraries from this window. It simply displays what is available in SharePoint. If you want more properties to appear in this window, you will need to add columns to your SharePoint list or library.
Default Behavior
By default, all properties with the same name are automatically mapped together. To change a mapping or to create a new one, simply drag and drop properties from the list of source properties to the right pane. Make sure to place them accordingly next to the desired destination properties.
Once saved, these mappings will be applied during the bulk edit. The value of the source property will be copied to the destination property. A green check sign will indicate if a source property is being mapped.
Multiple Mappings
If a destination column allows for multiple values, you will be able to merge multiple columns into one during the bulk edit. For example, two choice columns from the source list can be merged to a managed metadata column (considering the values exist in the term set used by the managed metadata column).
From Migration
The Property mappings window can also be opened from the Migration part of the tool.