In the lack of the clarification requested, I will provide you with a general answer.
You may find detailed information about how to register with a GP at the following page on the NHS's website:
However, it may happen that some GP practices are less "flexible" than others in the registration procedure.
It is also very important that you understand that registering with a GP does not mean to be entitled to free care from the NHS.
There are conditions to be met for that and, if they are not met, assistance could be quite costly, therefore this is something you have to carefully consider.
You may find useful information about visitors who do not need to pay for NHS treatment
on the NHS website (see link below), but I recommend that speak of this in detail with a GP too, or contact the NHS for further information:
I hope this information is helpful and I wish you the best.
Please do not hesitate to contact JA again if you need help and you may ask to speak with me directly if you wish ("For TheLawLDN only").
I would appreciate it if you could provide a positive rating, if you wish so of course.
Thank you very much.