add copyright notice to post metadata

Hullo! I have installed a child theme, and would like to add a copyright notice to each post entry's metadata (byline and date)

Have not yet found the php file where that metadata is set up. Can you direct me to the proper theme file?

Just starting to build this website. (see link below)

LOVE LOVE LOVE gppremium. Makes my website development life so much better. THANK YOU.

Take good care!