Copyright section provides a few options to customize the copyright content as well as disable the WordPress and/or theme credit links.
On the frontend, in the Admin bar, Customize.
On the backend, click Appearance » Customize.
Navigate to Copyright section.
Locate the copyright content textarea.
Specify the text to be displayed in the copyright section at the very bottom of the site.
The output is run through
wp_kses_post which means you can insert HTML.
Specify the horizontal alignment of the copyright content in its parent block element.
Optionally, toggle the WordPress credit link in the footer.
Optionally, toggle the author credit link in the footer.
Click the Publish button to save the changes.