The recommended way to remove the Powered by WordPress footer (or change it to something else) is by installing and activating the Claremont Child Theme from here: https://uxlthemes.com/docs/child-themes/
You can then override any of the claremont functions with your own code by going to Appearance > Editor. Select ‘Claremont Child’ where it says ‘Select theme to edit:’
Then select the ‘Theme Functions (functions.php)’ file and add your own php code below the /* write custom functions below here */ line.
This is the standard Claremont function which would need to be changed: