To get a mortgage when you’re self-employed, in addition to the typical mortgage requirements (such as good credit score, financial history, deposit, etc), you’ll have to provide additional documentation to evidence your income, such as certified accounts and SA303 forms to show you meet affordability criteria.
Most lenders will require you to prove your income by producing at least two years’ certified accounts (preferably prepared by a certified, chartered accountant), SA302 forms or tax year overviews from HMRC covering the previous two or three years (minimum), evidence of your upcoming contracts (providing you are a contractor), and/or proof of dividend payments and retained profits, should you be a company director. These can depend largely on the lender.
Other documentation you will have to produce will be a passport, a driving license, council tax bills, at least three months of utility bills, and at least six months’ worth of bank statements.