Invoice software for IT & digital services has to fit a workflow that rarely looks like a single flat sale: a project gets scoped, quoted, agreed, and only then invoiced — often for a client sitting in a different country and currency entirely. Send a quote for the scope of work, and the moment a client approves it, convert it into an invoice in one click, with the same line items carrying over so nothing gets retyped and nothing drifts between what was agreed and what gets billed.
A client based in the US or Europe expects to pay in their own currency, not to convert your invoice themselves before approving it. Set the currency per client, and issue every quote and invoice in dollars, euros, or whatever they actually pay in — your dashboard still rolls everything back into your home currency, so a month of clients across three currencies still adds up to one number you trust rather than three you have to reconcile by hand.
Thai B2B clients often withhold 3% at source before paying a services invoice, and if that withheld amount isn't tracked anywhere, your records never quite match what actually hit your account. Flag a client as subject to withholding tax, and the amount they withhold is captured on the receipt automatically the moment they pay — so a paid total that's short by 3% has an obvious, recorded reason, instead of becoming a mystery gap you chase down manually every month. The certificate and any filing with the Revenue Department stay with your client and your accountant, exactly as they already handle it today; the receipt just keeps the withheld amount on record so your own numbers reconcile.
Because the work is remote from the first conversation to the final payment, delivery has to be too — a client should be able to open a quote or invoice from a link and approve or pay it without downloading anything or creating an account first. If a project's scope shifts after you've already invoiced it, issue a credit note against the original rather than editing it quietly, so the full history — quote, invoice, correction — stays traceable the day a client's finance team asks for it, and export the whole thing in one click when it's time to hand records to your accountant.