In ultimate member plugin , I want to add a field that show the items the users uploaded , so I edited the default profile too add a new field and find that I can add a custom short code , I want to know where to write the function and codes of the short code , consider that I don't have access to functions.php file , so should I create a plugin that contains the codes? the profile fields (https://i.stack.imgur.com/Feuic.png) , the field where I should write the tag of my short code https://i.stack.imgur.com/P95bL.png)
I want to add the codes to my created plugin