To Customize Subscription recourses and permissions in Plesk, Please follow the following settings:-
1) Login to Plesk control panel.

2) Click on "Subscription".

3) Click on "Subscription"

4) Click on Customize button:

5) Click Resources Tab for Expiry Date, Change and allocate Disk space, Traffic, Mail, Darabase and etc.

6) Click Permissions for Enable and disable DNS, Mail management and etc.

7) Click Ok or Unlock & Sync.
For Flash Tutorial : Click Here.
