Step 1. Login your WHM as root.
Step 2. Click on Server Configuration.
Step 3. Click on CloudLinux LVE Manager Subicon.
Note:- Now you can increase ram by two way.
Process 1. For Specified user.
Step a. Click ok Users.
Step b. Choose domain name which do want increase RAM (single domain) and click on Edit option (as like pencil symbol) on left side.
Step c. Put your desired configuration in RAM box & click on save button.
Hence, RAM is increased and you can check in cPanel dashboard.
Process 2. By Specified Packages System (If you update RAM in specified package then RAM will be updated in all cPanel accounts which to be hosted from this package, not for whole cPanel accounts in your server.)
Step a. Click on Packages.
Step b. Choose a Package name which do want increase RAM (for all domain who assigned from this package) and click on Edit option (as like pencil symbol) on left side.
Step c. Put your desired configuration in RAM box & click on save button.
Hence, RAM is increased and you can check in all cPanel dashboard by one by one who assigned from this packages.