Multiple Devices with the same user.
Yes Drawboard PDF can be used on multiple devices(up to 10 with the same account), as long as you log into the same Microsoft Account you originally obtained it with.
Unless you are running a preinstalled version of the app(came with your device).
When you initially purchase a new app on the Store, you need to be logged on with your Microsoft Account. Here is how you can install the apps for other users.
Check this out too: Drawboard PDF: Can I sync my settings/favourites bar between devices?
Multiple users on the same Windows device
1. Log on with the other users account and open the Store App.
2. Right click in the Store App and select the Your Apps option at the top of the screen.
3. In the drop down menu, select Apps installed on <computer name>. This will display the list of apps installed on the computer. You will be prompted to enter your Store ID (This is the information for your Microsoft Account).
4. Select all of the apps that you want to make available for the other user account.
5. Click the Install Icon at the bottom of the screen and all of the selected apps will be installed for the other user account.
If you were looking to share it with other users on the same device but different accounts, this might help too: Sharing Windows 10 Store Apps with your Family