Hey there,
Thank you for keeping in touch
As an alternative you can directly edit the theme file.
In shapely > inc > extras.php
line 208-211, you can comment out this line of code which will remove the powered by colorlib and WordPress.
Leaving only the text in the footer customizer.
As suggested it would be best to do this with a child theme.
/*function sparkling_footer_info() {
global $sparkling_footer_info;
printf( esc_html__( 'Theme by %1$s Powered by %2$s', 'sparkling' ) , '<a href="http://colorlib.com/" target="_blank">Colorlib</a>', '<a href="http://wordpress.org/" target="_blank">WordPress</a>');
}
*/
Best Regards,
Support