I am not update macOS latest version
I am not able to udate Microsoft office, because need updated version macOS.
MacBook Air 13″, macOS 10.12
This will depend on the Year of the computer. Apple Icon on Desktop >> About this Mac will display the year. From there one can upGrade if compatible with a new macOS. Have a Look over Here for older versions of macOS and how to get it
Just make sure to do a Time Machine Backup Before attempting plus check if all Apps are compatible with the newer macOS