your username suggests you're in the UK.

So a) you already get a breakdown of NI contributions etc in you paystub and you can further check this on HMRC

and b) the house of Commons publishes everything tax related here: https://commonslibrary.parliament.uk/topic/economy-business/work-incomes/tax/

and c) there is Wall to Wall coverage of the budget every year, highlighted by the traditional annual photos of the chancellor of the exchequer and his red briefcase, in mid March when the tax year ends