Under Directive 451 the bank must give you the approval when you have not yet incurred any costs. It shows the bank's own offered mix and three uniform compositions defined by the Bank of Israel, with the rate, term and expected payments of each track, including the highest expected payment and the "forecast total interest rate". That lets you compare banks like for like.
Ask at least two or three banks for the same amount and term, ideally before you sign the purchase contract. The offer is based on the data you declare, so the bank will still check your documents and the property before the loan is final.
The pitfall is treating it as the loan itself. The terms hold for the period written in the document, at least 24 days from the date of the approval for you to provide the documents, so plan the signing inside that window.
Example
On ₪1,500,000 over 25 years, Bank A offers 4.5% and Bank B 4.3% on the same mix: monthly payments of about ₪8,337 and ₪8,168. The difference is about ₪169 a month, or about ₪50,800 over 25 years, enough to ask Bank A to match.