1) Log into cPanel.
2) Navigate to the Email section.
3) Select the Email Accounts icon.
4) Scroll down to the email address for which you need to update the quota resources.
5) Next to the desired email address, click Change Quota.
6) Either type in the new quota amount or select the Unlimited option.
7) Click Change Quota.
Once you have completed the above steps, the changes will be implemented immediately.