Webmail allows you to check your email inbox through the internet on any browser.
1. Login to your cPanel account.
2. Under the Email section, click Email Accounts.
3. Next to your email address, click Check Email.
4. Choose Roundcube (recommended), or Horde, and click Open.
This will bring you to your Roundcube webmail, where you can see your inbox, folders, options, and of course draft and send emails.
You can also access your webmail through your domain name by navigating to https://webmail.domainname.tld where domainname.tld is replaced by your domain name.