If it is a commercial house, just give the ID card, income certificate, marriage certificate or single certificate and household registration book to the developer. You don't have to do it yourself. If you sell second-hand houses, you also need these procedures.

The general bank loan conditions are

Your age+house age+loan period, male is not more than 60, female is not more than 55. The monthly income with proof of income must be twice the monthly repayment amount. If you have a spouse, the monthly income of two people is twice the repayment.

As long as 18 years old or older, you can apply for a bank loan.