When on the Fexa Desktop, you will first be able to locate this Move/Duplicate Line Item option by clicking on the hamburger menu to the far right
Next, choose the Invoice you want to move your line item to and save.
If you then navigate to the newly chosen invoice, you will see the Line Item has been Moved.
You can also duplicate the line item and then move it; both on mobile and desktop.
** Important to Note: Line items can be moved for Provider Invoices, Provider Proposals, Client Invoices, and Client Quotes. This option will only appear for users with update permissions on a specific line item. The same type of source invoices are restricted to their own. For example, Provider Invoice Line Items can only be copied to other Provider Invoices.