The mortgage deed is signed before a lawyer and filed with the Land Registry. The gov.il service lists the documents: the signed and authenticated deed, proof that the borrower is the registered owner (a Tabu extract), a fee reference and proof of local authority tax payment. Many banks file online. Your lawyer normally handles it.
If the property is not yet registered in your name, for example in a new building, the bank may take a caveat (hearat azhara) and a commitment to register the mortgage instead. When you buy from a developer, Directive 451 also requires the bank to check that you received the statutory guarantee under the Sale (Apartments) Law, or to tell you about it.
The pitfall is not checking the Tabu extract before paying: look for existing liens and caveats. After you repay the loan, ask the bank to cancel its lien and check that the extract shows it removed.
Example
For a ₪2,000,000 apartment with a ₪1,500,000 loan, you pay ₪500,000 from your own funds. The bank's ₪1,500,000 is released after its security, a registered mortgage, or a caveat when the property is not yet in the seller's name, is in place.