Paint 3D Preview is already available in the store, but only for PCs, and only for Fast Ring Insiders. This could change in the coming weeks or months as the head of the Insider Program, Dona Sarkar, reveals that a Paint 3D for mobile is there, but it is still in an alpha state and therefore not yet available, as reported by Windows Blog Italia.
The tweet was tweeted out a few hours ago and reveals that the app may be on its way. Alpha suggests it's still very buggy which means it can take some time before Insiders may see it.
not yet, it's in alpha mode still
— Dona Sarkar (@donasarkar) October 28, 2016
Windows Blog Italia also seems to have got their hands on a screenshot of the app running on mobile, but if it's just a concept or actual software is unknown.
The 3D Preview app currently available and downloadable but only for x86-64 CPUs which, in human language means that it is only available on regular computers and won't work for mobile.
If you're on a Fast Ring Insider build (above 14800), you can go ahead and download the app from the link below: