If you subscribe to Microsoft's Office 365 business service you will be licensed to use the software on 5 phones, 5 tablets, & 5 PCs or Macs.
You'll also get 1 Terrabyte of online file storage, and will automatically get new Office versions when they are released. To be honest, it's a bit of a no-brainer if you use Office applications regularly.
A big advantage if you want to work when travelling, is that you can use the software on any computer in the world as long as it has an internet connection.
I use it myself, and it's a superb service for £7 a month.
The free alternatives are Libre Office, or Open Office.