Creating a Function and Call It

PRE INFORMATION:

I am using WordPress and Divi.
I am using Child Theme.

I am building product pages with project feature of WordPress in order to display them to customers. There is no option to display project tags on a project page.

I want to add a function to functions.php of child theme which it calls and lists to tags of project. Then I will call this function on project page with the Code Module.

How I could do this? I have written some codes but they don’t work so I don’t add them here 🙂