How to get record Id from Lightning record edit form on record insert?

Hello Prachi,

Using the onsuccess event, you have access to the response object which contains, amongst other things, the id of the record that was recently created:

({
handleSuccess : function(component, event, helper) {
var payload = event.getParams().response;
console.log(JSON.stringify(payload));
}
})

For information:- Read here

Thanks.