How to change H3 tag in comments list and comments form title

Go to child theme

1. Install and activate your own child theme (what is this and where to get it?)
2. Copy file comments.php from your original BASIC theme into your child theme (this can be done via ftp or file manager in the hosting panel)

How to replace tag  in title of comments list

1. Open file comments.php of child theme for editing which you have copied earlier.
2. Find line 9 with title of comments list.
3. Replace H3 tag with P tag or any other which you want.

How to replace tag in title of comment form

1. Open  file function.php of child themefor editing or install and activate plugin FunctionsPHP and go to editing it
2. Add the following php function (H3 has been already changed to P tag in example, you can edit it as you wish):