Each principal builds a complete personal set — identity and civil documents, evidence of the specified benefit and eligibility, and whatever the USCIS instructions request — and signs their own filing. Shared items such as a marriage certificate can be copied into both, but shared documents do not merge the two independent principals’ eligibility assessments.
Two evidence sets, not one household bundle
Keep names, dates and spellings consistent across the two files, because inconsistency in the shared documents will surface in both. Where a document is not in English, supply a translation in each file rather than cross-referencing the other. If one spouse is instead included as a derivative, follow the family instructions for that case rather than assuming a second principal form is required for them.
The complete original message including sender information, every attachment unedited, the account details supplied, the identity claimed, and a dated note of anything said by telephone. The current published terms on the official government program page, the identity and licensing of anyone advising, and the payment instructions themselves. The first review should preserve the official instructions, receipt and identity of the payer, then keep them separate from employment, investment or immigration-petition records.