Actually, only one notaria is used for the closing, and the buyer has the right to choose the notaria. However, you may feel that it is more convenient to use the one who last registered the property, if you find that you are comfortable with that office and the individual notario. It is you choice as the buyer. Unlike in the US or Canada, neither of you are being represented. It is not an adversarial situation with lawyers involved on opposing sides. It is a simple transaction, but with strict management by a very specialized attorney, the Notario, appointed by the state, to insure that everything is done correctly. The notaria does not handle the funds. You and the seller make arrangements, possibly through a real estate agency, for the transfer of funds at the appropriate time. When that is confirmed and acknowledged, the closing will be finalized. Some weeks later, the buyer will receive the registered deed (escritura) from the notaria, unless a bank trust (fideicomiso) is involved for a property near a coast or border.