I am working on mscrm 2016 on-premise, when I change a field on multiple records (in the advenced find window) I see that the function connected to that field-change (onChange event) is not fired, it happenes only when I change my field on a single page but not on a multiple change, is there an option to fire onChange event in a multiple change ?
Bulk edit will not trigger form scripts, and this is expected (i.e. Product design/behavior).
In that case you have to move the business logic to the server side code (plugin or workflow) so it will execute on all transactions from SDK/API/ETL/UI rather than client side scripting which executes only from UI.