Cannot download Office 365 on macOS El-Capitan
I can't download it to my computer..


App Store page says OS X 10.6.6 or later is required.

After sign-in, https://portal.office.com/account#installs you'll see  two different links for Office download. One for MacOS Sierra 10.12 or later and another for 10.10 or 10.11. 

You can also see all available apps https://www.office.com/apps?auth=2&amp;home=1 and use their online version with our without simplified ribbons. I never used them, so can't say about functionalities. 


  computer is still not taking Mojave.


You can check compatibility for Mojave at https://support.apple.com/macos/mojave

For Sierra https://support.apple.com/en-us/HT208202

and for  High Sierra at https://support.apple.com/en-us/HT208969


  apple said it might be a hardware issue since I was practicing scripts on the terminal last year.


That is very broad.