I am trying to customise a registration form of a theme in wordpress. There is an authentication php file that has a return function with a form. I added an upload file field to that form. I even added a action="" with the folder destination ( in the form header). Sadly, i can click on it, i can make it required, but no uploaded file is send to the specified folder 'uploads'. I figured out that there is some custom js that handles the form validation and redirect automatically, if there are the right credentials. When I delete the custom js, all the registration credentials can be seen in the url. Unfortunately, my php knowledge is very limited. How can I easily add the upload file function to the form?