I am developing a small app (via xamarin.forms), and it will be required to access information held in an online server at any moment from the user's device. I have managed to create an azure sql database, however I have not found any way to edit it from the app. I did some research on connecting to azure via REST method, and all the guides corresponded to azure cosmos DB. Apparently they are not the same thing. I am using visual studio, and not azure mobile apps.
My question is: What is the difference between azure sql and azure cosmos databases?
Which is more suitable for a small scale app with limited finances?