That's no longer the case. As of today, Office enthusiasts on iPhone and iPad can get early access to the latest features. Users have to apply via a short survey, and the program will have a limited capacity.
“We have limited capacity in this program so we will largely offer these spots on a first come first served basis, to enthusiastic Office fans who want to test the apps on iPhone and iPad and provide feedback. Because of limited capacity and constantly evolving testing focus, we may need to remove participants from the program if they are not actively testing or we need to reallocate capacity/resources to a different test group,” said a Microsoft spokesperson.
Fast Ring Only
Users shouldn't sign up for the program unless they are okay with a bug or two. The program will be limited to Fast Ring build's which means a higher chance of issues. It's possible Microsoft will open out the program to everyone later on.
— MS Office Insiders (@OfficeInsider) January 9, 2017
The survey asks some simple questions such as your most-used Office app, device, and country. It also asks for the most common language, as well how frequently you use it.
Microsoft will be looking for users spread across most languages and continents, and more frequent users will probably be more desirable. There is one caveat, however.
Opting out of the Insider program results in the deletion of all Word, Excel and PowerPoint files from your local storage. Through cloud storage files will persist, this may be a deal breaker for some.
If you're happy to use cloud backups for the important stuff, head over to the application form. Let us know if you get accepted, it will be interesting to see who Microsoft selects.