What nationality are you?
Are you in employment? If so, do you earn more than £18,600.00 per month?
From the information you have provided, it seems that you have two options:-
1. Spouse Visa
2. Fiancee Visa
Both will require you to show an income of at least £18,600.00 in order to maintain and support your partner. If you do not have the required income, you will need to show substantial savings