How to set cookies in WP?

Question

WordPress

Can you tell me why you can't set cookies? Here it doesn't work.

setcookie('city_name', get_the_title(), time()+3600*24*7);

I found that it can be set via add_action('init', function() {}); but the problem is that WP_Query doesn't work in this function. And I need to set the value of the page name with an additional field in cookies. How can this problem be solved?