In github official(?) page, , says cordova plugin add cordova-sqlite-storage
And in some other posts, it says, cordova plugin add https://github.com/brodysoft/Cordova-SQLitePlugin.git
What is the right way to install?
I don't think the github link is the official Cordova repo.
The official list of Github repos for Cordova are here on Apache's Github
According to this, there is no official Cordova plugin for SQLite. So you can install one of your choice listed in the Cordova official plugin registry, or one you can find elsewhere if it seems good enough for your needs.
You can also use the one you specified, using cordova plugin add https://github.com/brodysoft/Cordova-SQLitePlugin.git