You have to install and activate the child theme first: https://theme.co/apex/forum/t/setup-how-to-setup-child-themes/57.
After that adding this custom code under
functions.php file locates in your child theme:
add_filter( 'gettext', 'x_edit_texts' );
$translation = str_ireplace('Category Archive', 'Your Spanish Text', $translation);
Let us know how it goes!