The State Pension changed on 6 April 2016 for people who reach State Pension age on or after that date. This is men born on or after 6 April 1951 and women born on or after 6 April 1953. The old rules (which include basic State Pension and Additional State Pension) were complicated, making it difficult to know how much you'd get until you were close to State Pension age. Not everyone will get the full new State Pension though, as it will depend on your National Insurance record.
Assuming you had made full National Insurance contributions, the State Pension for a single person in 2020/21 is currently around £759 a month. To put this in perspective, if you earn £22,000 now, your monthly income before tax and National Insurance deductions is £1,833, so your Basic State Pension will only make up around 40% of your current income. You may also be entitled to additional benefits through the State Second Pension.
This pension is payable from State Pension Age and is not included in the Lifetime Allowance.