Beyond the marriage certificate and passports, gather each person's current immigration documents, entry records and any prior applications, refusals or approvals. Add the spouse's employment contract, professional registration and evidence of income if the household relies on it. These records answer route questions early, before a filing strategy is chosen on incomplete facts.
Disclose the history before choosing the route
Earlier visa refusals, overstays or withdrawn applications change what is realistically available and how long each step takes. Give counsel the full history at the outset, including matters the household considers resolved. Translations of civil documents can wait until the route is fixed, but the underlying records should be located now, since certificates issued abroad often take weeks to obtain.
Keep originals together and note which authority issued each one. Assemble the source-of-funds material in parallel, because it is the longest task in the whole file and it belongs to the household rather than to any sponsor. Every tranche of capital should be traceable from a lawful origin, through the accounts it passed, into the enterprise, with sale agreements, tax filings, loan documents and bank records for each step.
Records held abroad, or by a former employer, or by an estate, routinely take months to obtain. Beginning that work before a project is chosen costs nothing if the project changes, since the material describes the investor rather than the offering.