Hello,

1. Copy the code from the screenshot: https://prnt.sc/KUoNqLmn1uCH
2. Paste to the functions.php file in the child theme: https://prnt.sc/i69h6GIAki1N
3. Either create a custom name for that function and add an appropriate code to show that form you want: https://prnt.sc/TgnN6dvEyLAg , https://prnt.sc/OqKzwgdo9qaG or copy the default function like there: https://prnt.sc/7fs_IjfBAA8u and add the needed content.

As a result, your custom content will appear: https://prnt.sc/1ram2W6lZplF

Kind Regards