Hi thank you for your message, I understand. I apologise, I misread your statement earlier and now note you are Mexican because you are from outside the EEA, EU or Switzerland and do not have indefinite leave to remain you can apply for a family permit however, you do not have to. You can still give notice of your intention to get married or form a civil partnership but the immigration authorities at the Home Office will be told.
The Home Office might ask questions about you and your relationship - if this happens you may need to wait up to 70 days before getting married.
In terms of the process, you should plan your ceremony - you can have a civil ceremony at:
a register office
any venue approved by the local council, for example a stately home or hotel
You must have at least 2 witnesses at the ceremony.
A registrar must carry out, or be present at, your ceremony. You can book a registrar yourself or the venue may do this for you.
The cost of a registrar is:
£46 at a register office
£86 at a registered religious building
Costs may be different at other approved premises.
Civil ceremonies can include readings, songs or music, but must not include anything that’s religious (for example hymns or readings from the Bible or the Torah). You can get a religious blessing of your marriage after a civil ceremony.
You must give at least 29 days notice before you get married or form a civil partnership - you can find out more about giving notice here: https://www.gov.uk/marriages-civil-partnerships/give-notice?step-by-step-nav=724aa735-c4cc-4ffc-9136-dcb43668982b
Whilst the documents you need to give notice are listed here: https://www.gov.uk/marriages-civil-partnerships/documents-youll-need-to-give-notice?step-by-step-nav=724aa735-c4cc-4ffc-9136-dcb43668982b
You must get married or form a civil partnership within 12 months of giving notice.
After you register, you can get a marriage or civil partnership certificate. It costs £11.
If you need a copy in the future you can order one online.
I hope this helps, if you can please accept my answer and rate me 5 stars (in the top right of your screen) then Just Answer will credit me for helping you today.