Some admins find the Registration Agreement annoying and wants to get rid of it. So here is a little trick. This will place a Register button at header, clicking on which users will get Registration page directly.

Go to template header_welcomeblock_guest and find this line of code:

<a href="{$mybb->settings['bburl']}/member.php?action=register" class="register">{$lang->welcome_register}</a>

and replace with:

<form action="member.php" method="post" style="display: inline-block;">
<input type="hidden" name="step" value="agreement" />
<input type="hidden" name="action" value="register" />
<input type="submit" class="button" name="agree" value="{$lang->welcome_register}" />
</form>

Save the template, done.