However, due to the nature of how the application is preinstalled on your device, it is not registered as the 'same' application as the Drawboard PDF on the Windows Store. So technically, although everything is identical to the application in the Windows Store, your preinstalled app is actually a 'hidden' application on the Store, and in addition is not linked to your Microsoft ID.
You will get the same updates as every other user of the application.
What you should NOT do
If you have the preinstalled version of Drawboard PDF on the Surface 3, do not uninstall Drawboard PDF for Surface on your Surface 3. If you do so, you can download a Trial of the 'normal' Drawboard PDF on the Windows Store and it will unlock for you, but if you uninstall the Trial, you may not be able to re-install it again.