Our services have a disk space limit. Inside that limit you can decide on your own how to use all the services (email, database, files, etc.).
To edit the quota of your email account login to cPanel, then scroll down to the "EMAIL" section and click on "Email Accounts".
First of all we will see a screen where you can create an email account. At the bottom of the form you can select the disk quota for the account. If you select unlimited the limit will be the disk space of your plan.
Scrolling down a bit more we can see a list of email accounts we already created. From here we can see how much space an email account is using and its quota. We can edit an email account quota clicking on the "Quota" link.
A new option will open that will allow us to edit the quota or set it as unlimited. To save your modification click on "Quota".