How to update PHP form when user click submit button?

How to update PHP form when user click submit button?

I have a form that updates data. When I click on update button, it updates
the data in the database but shows the old data in the form, and I have to
refresh the page again to view the updated data. If I change the action of
the page, it stops updating the data.
I want the update page to update data when the user clicks on 'Submit'
Button.
Kindly tell me the way to overcome this problem.
Thanks