statement of earnings/invoices

[xxxminty]

how often does a self employed person have to produce statements of earnings or invoices to the taxman?

[jedimistress]

When invited to do so. It may be never.

[dancecaller]

If you earn enough to pay tax you have to tell them.
Below a certain turnover you don't have to provide detailed accounts, just 3 figures
income
expenditure
capital allowance claimed.
Obviously you will keep your bills and receipts in case they want to see them later.
If you are employed as well as a buisness you can set buisness losses againt salary