Assuming you are running OS X 10.10 or 10.11 and MS 7, the procedure is the same for any of the iCloud enabled apps on the Mac.
In MS, when you do a save, if you look at the drop down menu at the top, one of the options is the MS iCloud. Just save the files there and they will be available on your other devices.
On your iPhone/iPad, from iOS 9 and onward with MS 7, make sure:
1) You are logged into iCloud with the EXACT same Apple ID as the one on your Mac.
2) You have iCloud Drive enabled.
3) That you have iCloud for MS turned on. Below the iCloud Drive on/off is a list of apps that you have given permission to use iCloud. MS needs to be on.
I use it all the time and it works very well. About the only caveat is that the new OSes only download something from iCloud when you use it. This is done as a space saving measure, which is handy. However, opening a file that needs to be downloaded first over cellular sometimes takes a bit, so be patient when you load a file for the first time on a device.