Archiving an invoice works in the same way as deleting an invoice.
To Archive an Invoice in the Web Portal, go to CRM > Invoices > Select the checkbox next to the Invoice you are wanting to Archive > select Archive Invoice(s) at the bottom of the screen.
You can also archive the invoice from the contact management portal, if you know the billing contact for the invoice you want to archive. Go to CRM > Contacts > edit arrow for the contact > Accounts > Invoices > select the checkbox(es) for the invoice(s) you'd like to archive > select Archive Invoice(s) at the bottom of the screen.
Note: An invoice cannot be archived in the App it can only be cancelled. Once it is cancelled it can be archived on the Management Portal. Ensure to use the filter on the Management Portal to see your cancelled invoice to then archive them.
To cancel an invoice in the App, go to Accounts > Invoices > swipe left on the Invoice > Cancel.