Sliced Invoices: pre-fill description field for new quotes

functions.php

add_action( 'sliced_after_description', 'si20211021_pre_fill_quote_description' );
function si20211021_pre_fill_quote_description( $cmb ) {
	global $pagenow;
	// only pre-fills new quotes
	if ( $pagenow === 'post-new.php' && isset( $_GET['post_type'] ) && $_GET['post_type'] === 'sliced_quote' ) {
		$field = $cmb->get_field( '_sliced_description' );
		if ( $field ) {
			$field->args['default'] = 'Text to pre-fill goes here';
		}
	}
}