I keep trying to download apps onto my MacBook. specifically, at the moment I am trying to download outlook however, every time I download it it says "null) can’t be installed on “Macintosh HD” because macOS version 10.14 or later is required." but when I go to the updates screen on my App Store it says I have no updates! Help I am so confused. This was my roommates MacBook and he gifted it to me.
MacBook Pro with Touch Bar
Additionally, what exact model/year is this laptop? And what OS version? If it is older, then your current OS version may be the latest it can handle.
Unless they set up that 'gift' so their ownership transfers, the user
(Admin) account would be in the original owner's name (still).
And may require a previous owner to help, to remove; should
there be firmware password, or other protections in place.
This path is what should have been done beforehand:
• What to do before you sell, give away, or trade-in your Mac - Apple Support
https://support.apple.com/en-us/HT201065
A usual start:
Erase & install a new/replacement system, not personalized.
Downloading apps onto my MacBook Pro
