Yes you can. Here's a small example.
Only labels, that you can't edit:
<DataGrid.RowDetailsTemplate>
<DataTemplate>
<DockPanel>
<Label Content="Age: "/>
<Label Content="{Binding Age}"/>
</DockPanel>
</DataTemplate>
</DataGrid.RowDetailsTemplate>
Here the label is replaced with a textbox so that the Age can be edited:
<DataGrid.RowDetailsTemplate>
<DataTemplate>
<DockPanel>
<Label Content="Age: "/>
<TextBox Text="{Binding Age}"/>
</DockPanel>
</DataTemplate>
</DataGrid.RowDetailsTemplate>