How to show button (different urls for different posts) only for mobile version of wordpress?

Question

WordPress

You need to make a button for the WordPress site, which will be displayed at the bottom of the screen only in the mobile version of the site.
The difficulty is that I need to insert different URLs into this button for different blog posts.
The theme is responsive. I did not find solutions for third-party plug-ins specifically for this task.

Answer 1

Add a custom field to posts and fill in the link there in each post https://codex.wordpress.org/Custom_Fields
Or use a plugin like ACF

Answer 2

As written above, add a custom field to the posts + to display only on mobiles, wrap the button in a special tag of the VI:

if (wp_is_mobile()) {
    echo '<button>Click</button>';
}