You may need photo ID, proof of address, recent household bills, your tenancy or mortgage details, and evidence of income or benefits. Some schemes may also ask for National Insurance numbers, bank details, council tax information, or recent meter readings. Requirements vary between energy suppliers, councils and government schemes, so check the relevant provider or the GOV.UK guidance before applying. Only send documents through official websites or verified contact details, and ask an advice service if you are unsure what you need.