Pension Tax relief for previous tax years in self-accessment

I was wondering if it is possible to claim Higher rate taxpayer Tax relief on pension contributions for previous Tax years via Self-assessment. I recently learned that it is possible to claim it up to 4 years back, but I am struggling to understand how to do it for tax years 21-22 and 22-23 as current tax return refers only to current tax year 23-24. Appreciate if you could let me know how to do it in current Tax return and how I can tell HMRC for which Tax year it is? Thank you

Hi ,
 

Details of how to make amendments to previous tax years Self Assessment returns at : Self Assessment tax returns   . Thank you .

To expand upon the admin's rather brief reply: You cannot claim for previous years within your current tax return. If you completed a tax return in previous years, but now realise you should have claimed relief, the window for making amendments to 22-23 returns via the software/website they were originally submitted by is still open. However the window for easy amendments to 21-22 is closed, and I think you'll probably be forced to send a paper letter about that... although do try HMRC Self Assessment webchat first just in case they're willing to do it that way.