Using a database in a Swift app to manage volunteers

To preface, I am very new to Swift.

I am in the planning process of building an app for my organization that manages our volunteers' information. I have read about using Realm or SQLite but my question is more concerning the upkeep of the database by those who manage the volunteers in my organization. Once the app is built and there is information in the database, how do people update it and keep up with it without having to log into the SQL DB. Is there a way to use any APIs to upload spreadsheets or CSVs to update the data?

Any help is welcome.