Based on all posted messages, here is an example of a ready-to-use file ( For example, create a file with name "save_address.php" and post this code is there ) :
- https://pastebin.com/zR42RyEk

But a tip, if you do not know PHP, entrust the work to someone who master the field, because it's a blow to integrate security vulnerabilities in your code ( And potential errors ).