Self Employed Invoice Numbering

JJRD

I am using quickbooks self Employed. I have been using different types of invoice numbering in the past such as using the invoice number according to the date (I.e 20210606 etc) and others I have matched the invoice numbers of my client. 

I recently found out that for tax you must have sequential numbering. Not sure what to do now with the stuff I already have? And I need to invoice a new customer so don’t know what to do? Please could someone give advise?

(Unfortunately QBSE doesn’t allow you to use letters - only numbers)

Pennywise

You can't change what you've already done, so leave history alone.  For new invoices, just set up your system with incremental numbering and think of a suitable start number, maybe something like 1001 then 1002 etc. then forget about it and let the system do the numbering.

Jeremy535897

The specific requirement for sequential numbering relates to VAT (see https://www.gov.uk/guidance/record-keeping-for-vat-notice-70021 ), but there are rules generally. See:
https://www.gov.uk/invoicing-and-taking-payment-from-customers/invoices-what-they-must-include