Source

File: wp-includes/category.php

function get_cat_ID( $cat_name ) { // phpcs:ignore WordPress.NamingConventions.ValidFunctionName.FunctionNameInvalid
	$cat = get_term_by( 'name', $cat_name, 'category' );

	if ( $cat ) {
		return $cat->term_id;
	}

	return 0;
}