What records do I have to keep digitally?

Every item of income and expense, with the amount, the date and the category, held in software rather than on paper.

That is the legal minimum for each entry. It is a digital version of what a decent landlord already keeps, rather than a new set of information.

You still keep the underlying paperwork as well: bank statements, invoices and receipts, in whatever form you like. Those do not have to be digital.

Keep everything for at least five years after the 31 January deadline for that tax year. The requirements are on gov.uk.