To do this will require modification of theme files which is beyond the scope of support provided.
I can only provide you with the file and line you need to edit.
If you have know coding knowledge kindly recruit someone to assist you with this.
You’ll need to edit the extras.php file located in sparkling > inc, line 208-211.
The function generating this code is
/**
* function to show the footer info, copyright information
*/
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>');
}
Hope this helps. Please ensure to back up your website before making any changes to code.