Changing Admin Name/password On Inherited Laptop

Hi gang, first time post!
We helped my father-in-law purchase a HP laptop (Windows 10) late in 2019. He was elderly and really couldn't connect with it. It basically sat unused until he passed and his wife recently gave it to me. I have all the paperwork from Best Buy including the password needed at startup to get into the machine. What I'm not sure how to do is get it all changed to my name with a new password. There's nothing that needs to be saved, as again, he never used it!
I really don't want to bring it back to Best Buy and pay to have them do it and my searches online offer different ways, but not being a big tech guy I'm not sure what's the easiest to pursue.
Open to suggestions!
Thanks in advance!

 

Not directly answering your question, but every laptop should have both an admin account, plus one standard account for each user.

1. Sign into the existing admin account. Change to a new password for security purpose.
2. Use the above admin account to create a new, "standard" account for yourself - preferably with a password.

Use (1) to load up new apps, customize, etc. until the laptop is 'just right' for you. From this point on, sign on as (2) for all day-to-day use. And use (1) only for installing more new apps and other admin functions.

As you know, it's very easy to accidentally click a link - and one or two wrong clicks are all that's needed for malware to download and install. When using as standard user, Win won't let malware install until it's approved by admin - giving you a second chance.

 

You can log in with the account that is on the laptop, then open Control Panel, User Accounts and add your own account, log out and log in with the account you created. The other option is to do a factory restore and during the setup you can make the computer account your own.

*If you're going to try using the admin account you might have to enable it via the command: net user administrator /active:yes

 

Going down the factory reset road as there are other things that seem odd as well.
Just want to say thanks for the responses!