Don't know how to add title_suffix I am working on existing Drupal project. I am begineer at Drupal and I need a help with something. In one node I've got title with title_suffix. This node is a view. I want to edit this title_suffix, but I don't know how and where to look at it. Could anyone help me please? Where do I have to looking for? UI or template files or where? Thanks.
Use a preprocess function to populate $title_suffix. It belongs in a file called template.php in your theme folder. 

Here's a primer: Setting up variables for use in a template.

A basic example that populates the variable $foo and makes it available to page.tpl.php (Drupal 7.x):

&lt;?php
function THEMENAME_preprocess_page(&amp;$variables) {
  $variables['foo'] = 'bar';      
}
?&gt;


The core module Contextual links populates $title_suffix in its implementation of hook_preprocess(). View source at modules/contextual/contextual.module for an example of how it is done.