When you log into your control panel, you will notice a set of modules arranged in rows. Each row pertains to a different a section of website and server management. Some of the modules which you will be using most often include the email module (where you can check your site's email and create new email accounts), the domain manager (which lets you assign new domains and manage your current list of domains and subdomains), redirects (which lets you assign specific redirects from one web page to another), and the FTP section (where you can set up access to your web server through an FTP client).
The aforementioned sections are just some of the many modules that you have at your convenience within the web hosting control panel. If you operate an online business with multiple business email addresses associated with your domains, then you'll most definitely use the email account module the most. You'll want to choose an email client that suits your needs. Most of the time, you can choose from applications such as Squirrel Mail.