[ig1]

It'll vary by country but in the UK sales tax (VAT) is generally paid based on the invoice date:

https://www.gov.uk/vat-record-keeping/time-of-supply-or-tax-...

You can do cash-based accounting and pay only when you receive the payment but this is only available to small companies (<1.35m revenue) and with some other restrictions:

https://www.gov.uk/vat-cash-accounting-scheme/eligibility