I am trying to fit this into a small screen

XAML Issue

<ContentPage
    xmlns="http://xamarin.com/schemas/2014/forms"
    xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
    xmlns:effects="clr-namespace:Handheld.Effects"
    x:Class="Handheld.Modules.Inventur.Page5130"
             Title="{Binding Title}"
             Visual="Material"
             BackgroundColor="{AppThemeBinding
                    Dark={StaticResource WindowBackgroundColorDark},
                    Light={StaticResource WindowBackgroundColor}}">

    <Shell.BackButtonBehavior>
        <BackButtonBehavior Command="{Binding BackCommand}" />
    </Shell.BackButtonBehavior>

    <ContentPage.Content>

        <ScrollView>
            <StackLayout Padding="10" VerticalOptions="Center"
                     HorizontalOptions="FillAndExpand">
                <Label Style = "{StaticResource DevLabel}"
                   Text = "{Binding DevInfo}" />
                <Label Text="{Binding LabMessage}"
                   Padding="10,16,10,0" />

                <Grid  Margin="0"
                      ColumnDefinitions ="Auto,*"
                    RowDefinitions ="*,*,*,*,Auto,*"
                       RowSpacing="0">

                    <Entry Grid.Row="0" Grid.ColumnSpan="2"
                    Style="{StaticResource Input}"
                           Placeholder="InvNr"
                    ClearButtonVisibility="WhileEditing"
                   Text="{Binding InvNr}"
                   Keyboard="Numeric"
                   Margin="16,0,16,15"
                   IsReadOnly="True" />

                    <Entry Grid.Row="1" Grid.ColumnSpan="2"
                    Style="{StaticResource Input}"
                           Placeholder="Platz"
                    ClearButtonVisibility="WhileEditing"
                   Text="{Binding DispLocation}"
                   Keyboard="Numeric"
                   Margin="16,0,16,15"
                   IsReadOnly="True" />

                    <Entry Grid.Row="2" Grid.ColumnSpan="2"
                    Style="{StaticResource Input}"
                           Placeholder="MatNo"
                    ClearButtonVisibility="WhileEditing"
                   Text="{Binding MatNo}"
                   Keyboard="Numeric"
                   Margin="16,0,16,15"
                   IsReadOnly="True" />

                    <Entry Grid.Row="3" Grid.ColumnSpan="2"
                    Style="{StaticResource Input}"
                    ClearButtonVisibility="WhileEditing"
                   Text="{Binding Descr1}"
                   Keyboard="Numeric"
                   Margin="16,0,16,15"
                   IsReadOnly="True" />
                    <Entry Grid.Row="4" Grid.ColumnSpan="2"
                    Style="{StaticResource Input}"
                    ClearButtonVisibility="WhileEditing"
                   Text="{Binding Descr2}"
                   Keyboard="Numeric"
                   Margin="16,0,16,15"
                   IsReadOnly="True" />

                    <!--<Entry x:Name="BScanFocus"
                        Grid.Row="5" Grid.ColumnSpan="2"
                    Style="{StaticResource InputScann}"
                            Placeholder="SSCC"
                    CursorPosition="1"
                   Text="{Binding Bscann}"
                   Keyboard="Numeric"
                   Margin="16,0,16,15"
                    TextChanged="BSCANEntry_TextChanged"
                   IsReadOnly="{Binding IsScanReadOnly}">
                        <Entry.Effects>
                            <effects:HideKeyboardEffect />
                        </Entry.Effects>
                    </Entry>-->
                    <effects:HideKeyboardEffectEntry
                      x:Name="BScanFocus"
                        Grid.Row="5" Grid.ColumnSpan="2"
                    Style="{StaticResource InputScann}"
                            Placeholder="SSCC"
                    CursorPosition="1"
                   Text="{Binding Bscann}"
                   Keyboard="Numeric"
                   Margin="16,0,16,15"
                    TextChanged="BSCANEntry_TextChanged"
                     Completed="BSCANEntry_Completed"
                   IsReadOnly="{Binding IsScanReadOnly}" />

                    <!--<Entry  x:Name="VPFocus"
                        Grid.Row="6" Grid.ColumnSpan="2"
                    Style="{StaticResource Input}"
                           Placeholder="{Binding TitleVP}"
                    ClearButtonVisibility="WhileEditing"
                   Text="{Binding VP}"
                   Keyboard="Numeric"
                   Margin="16,0,16,15"
                   Completed="VPFocus_Completed"
                   IsReadOnly="{Binding IsVPReadOnly}">
                        <Entry.Effects>
                            <effects:HideKeyboardEffect />
                        </Entry.Effects>
                    </Entry>-->

                    <effects:HideKeyboardEffectEntry
                      x:Name="VPFocus"
                        Grid.Row="6" Grid.ColumnSpan="2"
                    Style="{StaticResource Input}"
                           Placeholder="{Binding TitleVP}"
                    ClearButtonVisibility="WhileEditing"
                   Text="{Binding VP}"
                   Keyboard="Numeric"
                   Margin="16,0,16,15"
                   Completed="VPFocus_Completed"
                   IsReadOnly="{Binding IsVPReadOnly}" />
                </Grid>

                <Grid
                    ColumnDefinitions ="*,*"
                       RowDefinitions="*,*"
                       RowSpacing="0">
                    <Button   Grid.Row="0" Grid.ColumnSpan="2" Text="{Binding ButtonLeer}"
                         BackgroundColor="{DynamicResource Primary}"
                         FontSize="18"
                         FontFamily="FAS"
                         Command="{Binding FirstStartLeerOkCommand }" />

                    <!--<Button   Grid.Row="0" Grid.Column="1" Text="(F2) OK"
                         BackgroundColor="{DynamicResource SystemPink}"
                         FontSize="18"
                         FontFamily="FAS"
                         Command="{Binding BuchenBlockCommand }" />-->
                </Grid>
            </StackLayout>
        </ScrollView>
    </ContentPage.Content>
</ContentPage>