Follow the instructions below to install MySQLi on your VPS with WHM.
1) Login to WHM as the 'root' user.
2) Navigate to EasyApache by entering it into the search box at the top, left-hand side.
3) Scroll down and select a build option (a previously saved configuration), then click Customize Profile.
4) Select the version of Apache and click Next Step.
5) Select the version of PHP and click Next Step.
6) Chose additional options within the Short Options List.
7) Select Exhaustive Options List and look for MySQL Improved extension.
8) Click Save and Build.
This completes the process of installing MySQLi on your VPS with WHM.