Mortgage approval is always the first step towards buying a house! Without it. Buyers can NOT target the home price they are approved for. Finding a house first, then trying for the mortgage leads to failures. House sellers always want to know if buyers can pay.
Save yourself time and start with a lender. Mortgage approval amounts can vary from lender to lender. Its a good idea to get more then one approval opinion as there are bad approvals out there. A approval that goes to the underwriter is even better.
If not financing a loan and paying cash. A letter from your bank or financial institution stating the amount is required(proof of funds).
Here are some lenders. Rich Noto is not affiliated with them. You can use whoever you want.