Admin email roundcube problem

Hello, I have a site with Woocommerce. My problem is as follows. I do not know how to contact Roundcube email, so when potribitelite register wish forgotten password, make an order to receive an email. I know that must be taken Api Key but do not know how it works?

What do you need to contact RoundCube for? Roundcube is a webmail client, you’re not supposed to use it through your script.

Limited PHP mail() access is available if you need to send e-mail from your website. See this article for more information: https://infinityfree.net/support/email/php-mail