For those without a permanent address - for instance through being #homeless , #OnRemand in #prison or staying at a #MentalHealth facility - there are alternative ways of registering.

https://assets.publishing.service.gov.uk/media/663e1cbaae748c43d379391a/PF_ITR-N-S-C.pdf

You can only vote in the UK general election if you are 18 or over on the day of the election