Workflow Question with Unity and online Database

Hello,

I'm trying to make a game for a mobile device that mostly involves text. I'm curious if the best way to go about storing some of that data would be in a database, and also if Unity would be to access the database in the way I'm going to describe. I'm very new to databases so I have a lot of research to do on them, but I'm trying to make sure I'm going in the right direction first.

So basically I'd like to have the app have multiple lists of words. Users would be able to purchase more lists of words, and edit those lists as well.

So my thinking is that I would need a data base for user account information, such as username, password, number of lists allowed, and which lists are theirs. Then another one that actually stores all of the words. So would a database be able to accomplish this type of plan? A user logging into the app with their account information, and editing the lists within the app, updating the database to make it user friendly?

I thought about doing this with storing the data locally, and just having the user edit text files that the app would import/export. But then I wouldn't be able to limit how many the user can use or how they edited those text files.

Is there other ways to accomplish this that might be better? Would the original idea be feasible?

Thank you for reading!