In the UK if you're in full time employment and only have one job, then there's literally nothing to do. Not even clicking somewhere to approve your tax return - your employer does it all for you. I know people who are literally unaware when the tax year ends because they never in their entire adult lives had to do anything with the tax return - it's just completely irrelevant to a normal working person. And on the ocassion that you have to fill one out for whatever reason, most of it is already prefiled from the information HMRC holds about you already.