Change the title placeholder text for a custom post type

editor-placeholder.php

<?php
// Don't include opening php tag

//* Change Post Editor Placeholder Text
//**********************

add_filter( 'enter_title_here', 'pb_change_placeholder_title_text' );
function pb_change_placeholder_title_text( $title ){

	$screen = get_current_screen();

	if( isset( $screen->post_type ) ) {

		if  ( 'testimonials' == $screen->post_type ) {
			$title = 'Clients name';
		} elseif ( 'portfolios' == $screen->post_type ) {
			$title = 'Portfolio name';
		}

	}

	return $title;

}