Example of how to implement local database in your Xamarin.Forms applications - http://julianocustodio.com/litedb

MainPage.xaml.cs

        private void Get(object sender, System.EventArgs e)
        {
            Customers = _dataBase.GetCollection<Customer>();

            if (Customers.Count() > 0)
            {
                var customer = Customers.FindAll().FirstOrDefault(x => x.Name == EntryName.Text);
                DisplayAlert("id: " +customer?.Id, "Name: "+customer?.Name, "ok");
            }
        }