The house purchase agreement does not need to be stamped with the official seal of the Housing Authority, but the signed house purchase contract needs to be filed with the Housing Authority. The process of online signing is: 1. Property buyers will sign an online contract after confirming their intention to buy a house. 2. Print the formal (electronic) contract after the successful report of the purchase contract signed by the developer and the property buyer. 3. Development enterprises need to go to the real estate transaction management department to handle the contract seal filing procedures within 3 working days after signing the contract online.

Legal objectivity:

Article 490 of the Civil Code stipulates that if the parties conclude a contract in the form of a contract, the contract is established when the parties sign, seal or press their fingerprints.