If you are 18 or over and a genuine visitor, you can apply for your visit visa under Marriage Visitor Visa category. You can visit the UK under this category to;

• Get married
• Give notice of a marriage
• Register a civil partnership
• Give notice of a civil partnership

You will not be able to stay or settle in the UK after your marriage or civil partnership as you have to leave the UK and apply for your spouse visa to settle in the UK from your home country.