Hey Donna,
A lot of times when you buy a new HP or any other brand PC, it only comes with a short free trial for Microsoft 365 instead of a full permanent version of Word or Excel. Once that trial ends, the app locks you out and asks you to pay for the upgrade.
Did the receipt or the box for your computer specifically mention that a lifetime version like Office Home and Student was included in the price? Try logging into the main Microsoft website with your email and check the Services and Subscriptions section to see if you actually have an Office license tied to your account.
Let me know what you find there and we can see what is going on with your license.