Okay, here's my basic, general list of what you need to send. Of course, everyone's situation is slightly different, so you may need to tailor the documents slightly.
Also, they have changed the system so it appears you can now send copies instead of originals of supporting documents (a few weeks ago, it HAD to be originals), and there also seems to now be an option to upload your documents instead of mailing all of them
My document list:
Applicant (US citizen)
- Receipt for priority processing (if paying for priority)
- return shipping label
- Optional cover letter
- Printed online application form (don't submit until you have all the documents in your hands and are completely ready to mail the application package to Sheffield)
- Completed VAF4a Appendix 2 form
- Stamped Biometrics Confirmation Sheet (when you have attended the biometrics appointment)
- Receipt for IHS surcharge payment
- 1 passport photo of applicant (they can be US or UK size)
- US passport
- All previous passports
Sponsor (UK citizen)
- Copy of UK passport photo page
- Sponsor letter of support for the visa, outlining how you meet each requirement for the visa (financial requirement, UK accommodation details, short history of the relationship and reason for deciding to settle in the UK together)
Finances
- 6 full months of 401K statements showing at least £62,500 held for the entire time
- written confirmation from the 401K company that the money can be immediately withdrawn (with or without penalty)
Accommodation
If you will live with family or friends:
- a letter from the homeowner giving you permission to live there and stating that the home will not be overcrowded
- their Land Registry document
Optional:
- their latest original mortgage statement
Relationship evidence
- marriage certificate
- any divorce decrees, if either of you have been previously married
- 1 or 2 photos of you together, for example, one recent and one from early in the relationship
Evidence of living together for the last 31 years
For example:
- annual tax returns from each year
- house deeds
- utility bills
(I would send 1 document per year)
Sending evidence of living together for your entire marriage is important - we have had a couple of applicants refused their visas, despite being married and living together for over 20 years, because they only sent their marriage certificate and a photo, but no evidence that they actually lived together for 20 years.