I have filed the SA100 for tax year 2019-20. I now have to close the tax period in Quickbook to avoid changing figures in that period. How do I close the tax period?

Hello Adeel18mr, 

Welcome to the Community page, 

In the Self-employed account, there is no way of turning that period as closed. 

It would just be a case of making sure the transactions are dated within the new tax year period.