This type of visa allows your partner to join you in the United Kingdom purely to get married as long as your immigration status is in order.
Commonly known as a marriage visa in the U.K., a spousal visa is a settlement visa given to a wife or husband of a British citizen or U.K. resident.
While a U.K. marriage visa allows your spouse to come and live with you in the U.K., a fiance visa enables your partner to enter the U.K. for the purposes of marrying you.
A marriage visa is normally initially issued for two years and can be extended afterward. A fiance visa, on the other hand, is valid for six months, after which your new spouse can apply for an extension in the form of a marriage visa.
In order to qualify for a marriage visa, you must prove that you are legally married and are over the age of 21. A fiance visa also requires that you are over 21, you plan to get married in the next six months, plan to live together permanently and should have met each other before.