An AIP is pre-approval for funds
An AIP is a pre-approval of funds granted by a lender based on the financial situation of the applicant(s). No property needs to be found or chosen at the stage of getting an AIP - it's purely based on the calculation of the applicant(s) ability to repay the debt.
The mortgage offer is issued on the basis that the applicant’s financial circumstances will not change. It will be subject to the submission of updated documents and any change in the bank’s lending terms. In Spain, the bank will not proceed to the next step unless you have found a property.
We will need your supporting documents to ensure you will qualify for the mortgage you are applying for. At this point, you will not need to provide proof of deposit, so for example, you will not need to have sold your house at the time of application if you are using the proceeds for the deposit.