Form: Self Assessment: Employment (SA102).
The SA102 supplementary pages are used to report employment income when filing a Self Assessment tax return. This form must be completed by anyone with employment or directorship income to provide details for each specific role. You should include a separate SA102 page for every employment or directorship held during the tax year.
Source: https://www.gov.uk/government/publications/self-assessment-employment-sa102. Summarised automatically from the official source — general information, not advice.