You can access your website email online through your web hosting control panel, cPanel.  It comes with various website email programs to choose from, all accessible from any computer with an internet connection!  Step 3 below addresses another method of logging into your webmail from a direct link, especially good if you want to provide users on your web hosting account access to only their individual email account.

1) Login to your web hosting control panel (refer to logging into cPanel tutorial here).

2) From your web hosting control panel, click on the "Webmail" link/icon:

3) On this screen, click on the "Go to Secure Webmail Login" link:

As noted on this page, you could also access your webmail directly by going to the url https://[your-domain-name.com]/webmail .  For username/password, either enter in your web hosting account username/password for access to all created emails in the account, or your email address/email password for access to that email. However, in that case you will have to enter in that individual email account username/password, and you only get access to email from that email address.

By logging into your web hosting control panel using set 1 and 2, you also get access to the webmail for all the created email accounts on your website.

4) Here you are given several webmail programs to choose from!

Horde is a quick email program to use.  Roundcube displays/sends html email.