On your iPhone, go to the App Store.
On the Search option, enter Office 365 and search.
Native versions of the Microsoft Office suite are available for downloading for iPhone and iPad. However, Microsoft no longer offers to download the entire Office suite as a complete package through the Apple Store - each application must be downloaded separately. So when searching for the particular product you want, just be sure to download the apps with the icons seen below in order to ensure that you are getting the official Microsoft-owned product.
For any questions, please feel free to contact us at firstname.lastname@example.org