mac os upgrade

i have a mac book late 2011 model. The present Os is high sierra Version 10.13.6. I got my macbook serviced today and they formatted the HD.

I am unable to install office 365 and it says "(null) can’t be installed on “Macintosh HD” because macOS version 10.14 or later is required."

is there anyway i can upgrade to version 10.14 ?