Upon collecting your passport from the VFS Centre, you will receive a vignette Visa (full-page sticker) in your passport which will be valid for 30 days to allow you to travel to the UK.
It will be printed on a Biometric Residential Permit (BRP) in the form of a standard-sized card. The location of collection will most probably your university (with ACL code in the Visa application) or be a designated post office (as indicated in your notification letter). The BRP must be shown along with your passport whenever you travel in and out of the UK.