MVVM data/connection passing

[ptnavratil]

I am creating WPF application (using WPF UI library) with CommunityToolkit.MVVM targeting .NET 6+. I dont have much experience with MVVM/Community Toolkit and i would like to ask few questions.

In general how to pass data between different ViewModels? For example filling some input fields in one page and then sending the data to another page.

How should i handle Database Connection (using standard System.Data.SqlClient.SqlConnection) to make it available in different views of the appliction? I would like at application startup display page where user choses database connection (stored in some configuration file in app folder) and then clicks button and if connection is successfull then its navigated to "main" application page.

thank you very much