What is to be considered by most bank/emi/brokers discussed in this forum as valid source of funds for digital freelancers?
Would local tax declaration work or they may go down deep requesting chat with past clients, contacts, PII..?
Copy of agreement with clients and invoices you have issued to clients are usually enough. Tax returns are sometimes also requested.
If they start asking for things like proof of work, consider whether that particular financial institution is right for you. I've seen such requests and that's usually a sign the institution is a bad match.