Lets say I have a form in form.php and when I click submit all inputted data is sent to model.php for database manipulation etc.. and then when everything is done the model.php redirects user back to form.php using function:

header('Location:form.php');

How in the blazing hell can form.php recognize I was redirected there from model.php ? I am so lost about this for so long now, I tried $_SERVER['HTTP_REFERER'] and everything and I just get an echo with my current page location. I want to get an echo of the model.php on my form.php