To read, edit any Microsoft office file in desktop, its very easy. But imagine same work on android phone. Firstly due to different operating system & secondly smaller screen size, it becomes little bit tough to do the same.
Here this app can serve you better - Officesuite.You can create, edit any Microsoft office file like word, excel, power point, even pdf etc. You can put formula in excel.
You can insert chart, diagram in excel file. You can read presentation file in mobile. You can create & open password protected files.
What else you want. All this free of cost. There is also pro app which you will need to purchase, you can have many more access to features.
You can print your excel or word file with printer command. You can directly convert word or excel file to pdf & can send as an email.
I like this app very very much. There always comes default app in android, where in you can perform these functions but you get restricted access normally. So I prefer Officesuite. I recommend to all my readers.