In may centralized finance systems we can pay via invoices, but in ethereum I missed that in may cases so I decided to build a one, a simple standard to create, pay, cancel invoices which users can use it to pay invoices with specific token, and amount of it as well
The standard example can be found at : GitHub - ProgramFilesx86/example-invoice-standard
Create : to create an invoice
Pay : to pay a specific invoice
Cancel : to cancel a specific invoice
this standard can be implemented as contracts by tokens (as such usdc / dai) so users will use it to pay their invoices with such tokens, the token company will have fees as well
and many other cases can be used