I've recently gone through this myself — it's a bit of a hassle, but manageable. If you're using a payment platform like I used to
boost bill pay then they provide transaction reports that are exactly what you need. You'll find breakdowns by country, tax rates, and amounts — this forms the base of your sales tax report. To file, you’ll need invoices, sales reports, and account statements from the payment provider. The sales tax report is usually filed quarterly, depending on your country or state — in the U.S., it's called the Sales and Use Tax Return. Just don’t confuse it with VAT if you're dealing with Europe — different rules. My first time doing it, I spent all night matching numbers manually to Solidgate’s data, but now I’ve automated everything in a spreadsheet.