Hi fellow Ubuntu user,
Glad that you are looking for something to help you educational wise.
There are many office suites you can choose from. I personally (this is just my opinion) recommend Ubuntu's default office suite, Libre Office. It's free and open source. Libre Office supports the file formats of most other major office suites, including Microsoft Office.
Another one is WPS Office. It is the default office suite in Ubuntu's offical flavour: Ubuntu Kylin, for Chinese users.
However it is not fully open source and it's other versions are not free. If you do not like proprietary software, then I'd go with Libre Office.
WPS Office claims that they support many of the file types that Microsoft Office uses, but I've read many angry comments and reviews that it doesn't. So I'd keep this in mind.
I've also heard of other office suites on different desktop enviroments such as, KOffice, Gnome Office etc. But most linux distros come with Libre Office. And I don't know if KOffice or Gnome Office would work well with Ubuntu's desktop enviroment Unity, but I could be wrong so you could try them out if you'd like.
Hope this helps!
Also keep in mind that if you are looking for a office suite to use for school, high school, college, etc. Some schools have requirements for what office suite you use. If they discover that you are using something different it could be bad news. But since Libre Office etc. are compatible with most file formats it shouldn't be a problem. But I'd check in with your teacher first.