To increase your customer's disk space through WHM please do the following:
- Login to your WHM (Web Host Manager)
- In the left menu, under "Account Functions" click Quota Modification.
- Select the username or primary domain of the account whose disk space quota you wish to modify and click Modify.
- You can also click "Show all accounts" to change the disk space quota for multiple accounts.
- Adjust the disk space quota to the desired value and click Save.
You can also change the disk space quota of your WHM packages to increase the quota for multiple users.