I am not experience wiht PHP, have just started using it last week. I'm trying to find out how to call a function for submit button. Using html and php I've created a form that has a table which displays some data from MySql. When new information is selected using drop down menu, the field in table has changed accordingly, but I need a code for the "Submit button" to update that information in database. I have an update query that it should work, and I have created the image of the button using html.

I don't know how to code function/trigger for submit button in php. Any feedback is welcome. I need this urgently