As an employee I have only heard of PAYE, which is having your tax and NI payments deducted from your salary by your employer each month, 'taxing at source'
The only alternative I know of is where someone is self employed and HMRC send a tax demand twice a year based on the previous years earnings, although nowadays they also require an advance payment on the current years earnings.
DH and I were in the workplace for nearly 80 years between us, with DH working both an employee and self employed at various times and these are the only tax regimes we are awre of.
