How To Change an email Quota
To change a mail quota, perform the following steps:
1 – Open cPanel (yourdomain/cpanel).
2 – Click on (Email Accounts) from Email section.
3 – Click on Disk and Quota.
4 – Enter the new email quota, in Megabytes, in the appropriate text box. For an unlimited account, click unlimited.
5 – Click Save to store the new value.