Supporting documents are submitted with Form I-140G through the official portal once USCIS issues instructions, and further items can be requested later. For a couple, that generally means civil records establishing the marriage alongside each person's identity and background documents. Gather originals, certified copies, and translations early, but file according to the official instruction list.
Fix name and record inconsistencies early
Married couples often carry paperwork in two versions of a name, or hold documents issued in different countries and languages. Reconcile those now: match the passport spelling to the marriage record, obtain certified translations where needed, and note any document that will take months to replace. Decide which items to order immediately and which to leave until the official instructions arrive, so the couple is not paying twice for the same certificate.
Build the funds narrative jointly and separately at the same time. Where assets are held in common, the record should show how the couple came to hold them, which is often a longer story than either spouse's individual earnings — a business sold, an inheritance, a property held for decades. Where an asset belongs to one spouse alone, keep its documentation in that person's file instead of merging everything into a single household folder.
Hypothetical example: a couple's principal asset is a company sold eleven years ago, and reconstructing that sale — the agreement, the completion statement, the tax treatment, the subsequent movement of proceeds — takes longer than every civil document combined. Order the work by how long each item takes to obtain rather than by how important it feels.