1) Log into cPanel at:
Note: Replace domain.com with the Primary Domain added on your account.
2) Once logged in, you can find “Email Accounts” icon under “Mails” tab. Click on that “Email Accounts” icon to find the list of email addresses added on your account.
3) Click on “Change Quota” option associated with the mail account for which you want to change the mail space limit.
**If you wish you can use the “Search Email” box to find your email address from the list.
4) After you click on “Change Quota” option, you can enter the Mailbox Quota as per your requirement and click on “Change Quota” button.