Apply for British citizenship if you're married to, or in a civil partnership with, a British citizen - form AN, who's eligible, fees and how to apply. Use this guide if you are looking for records of how, when or if a person obtained British citizenship up to October 1986.Your long-term partner must prove they have permission to be in the UK to apply to the EU Settlement Scheme. If you are a U.S. citizen, once you file Form I130, your spouse is eligible to apply for a nonimmigrant K3 visa. Information for University of Oxford staff about applying for British citizenship after they are granted Indefinite Leave to Remain (ILR). Customers applying for a UK Visa from the USA may visit one of over 130 USCIS Application Support Centers to provide their biometric information. However, you must be at least 18 years of age and have a residence (domicile) in the U.S. before you can sign the Affidavit of Support (Form I-864 or I-864EZ). Failure to complete this may result in a delay to your application. Students can use this tool before lodging an application to find out what documents they need to attach to their application. Check your state's deadlines here!