To set the email quota on specific email address,please follow the following steps :-
1) Login to Plesk control panel.
2) Click on "Subscription".
3) Click on "Manage Hosting" in front of the domain whose files permession you want to change.
4) Click on the "Mail Tab" and Click on email address for whome you want to set the mailbox quota.
5) Select the box in front of "Specify new size" under "Mailbox" option and enter the amount of space you want to give to that email address.
6) Once you have entered the amount of space click on "OK". The quota has been set on the email address.
Note:- By default the quota is selected as Unlimited which means that this email address may use any amount of space provided to that domain.
