Is this for entry visas from outside the UK (spouse, Tier 2, Tier 4., etc.)? Or if you lose your BRP and need to re-enter the UK?
There is this too
https://www.gov.uk/biometric-residence-permits/overviewOverviewYou must have a biometric residence permit (BRP) if you want to:
apply to come to the UK
apply to extend your visa or settle in the UK
transfer your visa to a new passport
apply for certain Home Office travel documents
You don’t have to apply separately for a BRP. You’ll give your personal data when you make your visa or immigration application.
What’s on your BRPYour BRP will include:
your name, date and place of birth
your fingerprints and a photo of your face (this is your ‘biometric information’)
your immigration status and any conditions of your stay
whether you can access public funds (eg benefits and health services)
You can use your BRP to confirm your:
identity
right to study or work in the UK
right to any public services or benefits you’re entitled to
Your BRP will be sent to you by post if you’re making your immigration or visa application from inside the UK. If you apply from outside the UK you’ll have to collect it from a Post Office in the UK.