Invoice DRAFT or PAID, how to add new status?

Will like to add a new status for invoices apart from DRAFT or PAID, is this possible and how?

The idea is that when invoices are listed, you can visually see and quicly identify (without clicing into the invoice detail) what status is the invoice at. For our needs, we have 2 online contributors that work in a two process invoice creation, so the status can help showing if invoice is at step 1 or 2.

Is there an APP for this?
Can this be done in DB easily?

Any advice will be appreciated, thanks

Juan