apply_filters( 'wpforms_coupons_generator_generate_code_args', array $default )

/**
 * Allow modifying coupon code generator.
 *
 * @link   https://wpforms.com/developers/wpforms_coupons_generator_generate_code_args/
 *
 * @param array $default     {
 *                           Array of default settings.
 *
 * @type string $prefix      Text before the generated coupon code. Default empty string.
 * @type string $suffix      Text after the generated coupon code. Default empty string.
 * @type string $characters  Characters which will be used to generate coupon code. Default 'ABCDEFGHJKMNPQRSTUVWXYZ23456789'.
 * @type string $code_length Generated string lengths.
 *                           }
 * @return array
 */

function  wpf_coupons_generator_generate_code_args ( $default ) {

	// Set your defaults below
	// Default prefix for the coupon
	$default[ 'prefix' ]      = 'WPFORMS-';

	// Default suffix for the coupon
	$default[ 'suffix' ]      = '-COUPON';

	// Default allowed characters for the coupon
	$default[ 'characters' ]  = 'ABCDEFGHJKMNPQRSTUVWXYZ23456789';

	// Default length for the coupon
	$default[ 'code_length' ] = 20;

	return $default;

}

add_filter( 'wpforms_coupons_generator_generate_code_args', 'wpf_coupons_generator_generate_code_args', 10, 1 );