Hello everyone, please contact me as I can insert the terminate button See Image http://prntscr.com/if9gin

 <span style="margin-left:5px;"><?php printf(__('Accetto i <a target="_blank" href="%s">termini e condizioni</a>', 'terms'), osc_get_preference('terms_page', 'terms')); ?></span>
    </div>
   

<span style="margin-left:5px;"> <button onclick="window.location='http://link/'">Accetto Termini e Condizioni </button>
    <?php

@Fabio
You can use our Custom Attributes Plugin and create checkbox field with 1 value that is required, however not sure if you can put link there, just if you format it as html.

Test on demo

I'll explain . I would like to put blue button (the one on the right) instead of the left one and more beautiful aesthetically and you see better http://prntscr.com/if9gin

@Fabio
It's nice what you want, question is what you did for that. Noone will do your job, people can just help you, not provide you solution based on your screenshot,... it's support forum.

I solved it myself  http://prntscr.com/ifgtj4