How to add multiple command on a single button

i am working on a college project of hotel management
in that i made a form of check in in which the details will be entered and there is a submit button
i want that after clicking on submit button my data should be saved and also i want a message box to appear of registered successfully
my data is getting saved but i am not getting how to add that message box

by using this click_me function i am adding values to database

Don’t know much about back-end but putting both the functions in a single function and then calling that function on submit might work.