Up to the 31st December 2024, proof of immigration status was a physical document called a Biometric Residence Permit (BRP). From the 1st January 2025 BRPs have been replaced with an electronic visa (eVisa).
An eVisa is an online record of your immigration status and the conditions of your permission to enter or stay in the UK.
You have to create a UK Visas and Immigration Service (UKVI) account to be able to access your eVisa and create share codes to prove your right to study, work and rent in the UK.