Move a single file via the file options ellipsis:
Click the file options ellipsis.
Select Move to Library.
Select a destination library from the Select Library dropdown menu.
Click Next.
Populate custom fields, if applicable.
Click Move.
Move multiple files via the bulk actions button:
Select one or more files.
Click the caret next to the bulk actions button.
Select Move to Library.
Select a destination library from the Select Library dropdown menu.
Click Next.
Populate custom fields for each file, if applicable.
Click Move.