Try downloading office 365, then when it asks you to login use whatever your work e-mail and password is. Worked for me. Or your kids school login. Only downside of that is it brings up dead links to all my work files on my home laptop (which can’t connect to the work servers).
Word (and I think excel?) docs will open in an online editor (a bit like google docs).
I’d steer clear of google docs/libre/open office, they’re great but they won’t run macors and the formulas are different in excel so any maths/science type stuff using those won’t work, and kids may as well learn to use the software they’d actually use in the real working world, which inevitably is MS Office.