With an easy-to-use interface, the user should configure the account he wants to manage, the details for each transaction he puts inside, and the budget goal based on categories.
We could expand this application with many server-side additions, such as the direct download of information from the bank account, or the synchronization of the data with the family (in this case, we need an authentication system).
MVP is defined as the product with only those core features that allow the product to be deployed, and no more.
This is the list of the features we need for our MVP:
The application is for a single user
A user can create many accounts
A user puts information about each transaction by hand
A transaction is represented with a date, an account...