Profile: alexanderS-9

Problem: I would like to display the title of the post selected in a post reference field using PHP, but when I output the value of types_render_field I get a number.

Solution: This number is the referenced post ID. You can use it to get the post title with the WordPress function get_the_title:

$tarif = types_render_field( "tarif" ); 
$title = get_the_title($tarif); 
echo ucwords ($title);

Relevant Documentation:
https://toolset.com/documentation/customizing-sites-using-php/functions/
https://developer.wordpress.org/reference/functions/get_the_title/