In parts of Europe, they are using pro-forma invoices, is similar to the quote but it is much more needed for financial dept. Where the quote can expire in 14-30 days, a pro-forma have to be paid before applying certain services.
Take it as invoice: draf, sent, viewed, paid
for instance, when im issuing a pro-forma invoice, the financial dept. of the client, can allocate and lock the amount of that pro-forma invoice. so when the pro-forma invoice is paid, then, that will convert to the paid invoice, and that`s what counts for the financial dept, as they need both pro-forma invoice for quoting services and the final invoice after the pro-forma has been paid.
Also, revenue office wont consider a quote, but it will take a pro-forma invoice and a paid invoice as receipts.
similar things with POs for quotes.
so a workaround to this, i think we can set invoices tags that will just show on the corner (draf, pro-forma, paid etc)