edd_add_email_tags.php

<?php

/***
Add custom email tags for use in EDD email templates
***/

function drw_edd_add_email_tags() {
	
    edd_add_email_tag('product_message', __('Custom product message','drw'), 'drw_product_message_email_tag');
    
    edd_add_email_tag('product_message_2', __('Another product message','drw'), 'drw_product_message_2_email_tag');

}

add_action('edd_add_email_tags', 'feti_edd_add_email_tags');

/***
The {product_message} email tag
***/

function drw_product_message_email_tag( $payment_id ) {

    $payment_data = edd_get_payment_meta( $payment_id );
    
    $email_tag_content = __('This is a custom message','drw');

    return $email_tag_content;

}

/***
The {product_message_2} email tag
***/

function drw_product_message_email_tag( $payment_id ) {
    
    $email_tag_content = __('This is a another custom message','drw');

    return $email_tag_content;

}