I was able to resolve the issue though I've been unable to confirm exactly why it was fixed: Troubleshooting- When signing in to any of the preinstalled Office apps with my Microsoft account, no evidence of a valid key was presented. I was prompted to begin an Office 365 trial. - A Dell rep informed me that Dell issues the Office activation key to a Microsoft account based on the email address that I used to place the order. This is a very poor policy and should be changed if true. The documentation presented to me at the time of order suggested that the key would be emailed to me. There seems to be some conflicting information about how this process is handled. Any Dell rep reading this, please pass this feedback along to avoid confusion in the future. - I signed out of my primary Microsoft account and into the account corresponding to the email I used during the purchase. A complication to this is that I actually already had a Microsoft account under that email. Either way, this did not fix the problem and the apps still showed no sign of an activation key. - The Dell tech support rep had an excellent idea to create a local account not tied to any Microsoft account. Upon signing into this local user account (with no ties to any Microsoft account), the preinstalled Office apps notified me that a license for Office 2019 was available and could be activated by signing into a Microsoft account. - I signed in to my primary Microsoft account (not the one supposedly tied to the email I used at the time of purchase) and the license now seems to be properly tied to my account. ConclusionThe Office key seems to be tied to the computer itself but for some reason I was not able to see it until I was signed out of all Microsoft accounts. Once I was totally signed out and inside of a local user account, the preinstalled Office apps recognized that a valid license was available. Upon signing in to the Office app with the  Microsoft account of my choice, the license seems to be active and properly tied to my Microsoft account. Note: I have not been able to find confirmation that the Office Activation Key is preinstalled before delivery of the XPS and must be claimed by tying it to a Microsoft account. I have also not been able to find an explanation for why I was not able to claim the key on my primary user account.
BackgroundI recently purchased an XPS 15 7590 with Windows 10. Along with the purchase, I also bought an Office 2019 activation key. The Office apps (Word, PowerPoint, Excel) were all installed when I received the laptop. When I open one of these apps, I'm prompted to activate my Office license to use the products. ProblemMy plan is to install Linux over top of Windows and then run Windows in a virtual machine. I will then activate my Office products inside of the VM. My problem is that I'm not sure how to extract the Office activation key and I don't want to lose it when I replace Windows with Linux. Questions  
Extract Preinstalled Office Activation Key