How Can Someone On SSDI Legally Move to the UK?

Now I know do to an agreement between the US and the UK that people on SSDI can still receive their Social Security Disability Income payments while living in the UK, meaning that anyone on it can pay their own way so would not be a burden. So I just am looking for answers as to how someone on SSDI can legally move to the UK?

Hi enflores
Please direct your question to the Home office.
Conact details can be found here:
Contact UK Visas and Immigration for help
Thank you.