A Marriage Visitor Visa is designed for people who simply want to get married in the UK, irrespective of whether either of them is a UK citizen. (e.g. a couple from Australia or the USA might simply like the idea of having a marriage ceremony in a British stately home or castle). The granting of such a visa is totally unconnected to either partner's right of residence in the UK:
https://www.gov.uk/marriage-visa
If you wish to remain in the UK after your marriage, a Marriage Visitor Visa isn't the one you need. You should apply for a Family Visa:
https://www.gov.uk/uk-family-visa/partner-spouse
Most countries, including the UK, only accept visa applications from people who're outside of the country. However I note (from my second link above) that there's an online process available for people who're already in this country, so perhaps you could use that?
When you've been married for 5 years (and living in the the UK) you can then apply for indefinite leave to remain here.