If you have accepted the default option while installing Ubuntu, or that your computer comes with Ubuntu pre-installed, chances are that your Home folder and the system folders all lie in the same partition. This is perfectly fine, but if you want to upgrade your existing Ubuntu version, or reinstall Ubuntu, you won’t be able to preserve your app settings, or even retain your files and documents. One of the good practice is to give the Home folder its own partition, so whatever changes you made to the System folder won’t affect your Home directory, and you can easily upgrade or reinstall Ubuntu with ease.
If you want to move your Home folder to another partition, here is how you can do so.
How to Move Your Home Folder to Another Partition [Linux/Ubuntu] (Make Tech Easier)