How to root LG K7 (MS330)? I have a cleaning program on my phone and one of the program functions is to optimize CPU.When I try this, it says I do not have root privileges.

How can I get root privileges on my android LG MS330 ?
I'm suggesting something similar to what @Gokul NC has suggested. I'm assuming you have a computer, so this is a better option with a higher chance of successfully rooting.

Access your computer, go to the browser, and download Kingo root from https://www.kingoapp.com. Once it's downloaded, install the program, connect your device, and you'll be given further instructions within the app. 
I have tested this method more than 10 times, you should experience satisfying results.