Is Microsoft Office free for mobile phones and tablets ?

Is it possible to download and use Microsoft Office applications on mobile phones and tablets for free ? I need to use Word and Excel in my mobile devices, at least for viewing / reading of the files.

Microsoft Office applications for mobile phones or tablets are available to download and use for free. You can download Word, Excel, PowerPoint, Outlook apps for Android or iOS. These apps work with a newer Android versions.

To use the Microsoft Office apps on smartphones or tablets for free of charge, the screen size of device should be 10.1 inches or smaller.