“wpcfe_print_html_head” hook is used to add custom styles to print PDF Templates.

function wpcfe_print_html_head_style_custom_callback(){
    ?>
    <style type="text/css">         
		p{
			font-family:'Source Sans Pro' !important;
			font-size: 22px !important;
			color: #244e54 !important;
		}
    </style>
    <?php
}

add_action( 'wpcfe_print_html_head', 'wpcfe_print_html_head_style_custom_callback', 20, 1 );