Send evidence that:

comes from the government, a bank, landlord, utility provider, or a medical professional
confirms your relationship with your partner – for example, that you live together, share expenses or are married or in a civil partnership
is less than 4 years old
You can use things like:

a marriage certificate or civil partnership certificate
a tenancy agreement, utility bills or Council Tax bills confirming that you live at the same address or pay bills together
a bank statement from a joint bank account, or confirming that you live at the same address
a letter from your doctor or dentist confirming that you live at the same address
If you do not have any evidence that meets these criteria, there is other evidence you can provide instead, including:

a one-off bill like vet’s fees or home repair costs
letters confirming you and your partner are on the voting register for the same address
student finance paperwork confirming that you live at the same address
If you do not live together

If you cannot live together because of work or study, or for cultural reasons, you’ll need to prove that you have an ongoing commitment to each other. You can do this by providing evidence that you:

communicate regularly with each other
support each other financially
care for any children you have together
spend time together as a couple, for example on holiday or at events