Apple iOS 11 introduced the HEIC is a subset of HEIF (High Efficiency Image Format). At present, Educa does not support this file type, but there are two work-arounds: (1) Change your Apple device settings, (2) Convert your HEIC image to JPG.
Change Phone Settings to Allow Other Formats
Go to Settings > Camera.
Tap "Most Compatible." This setting is available only on devices that can capture media in HEIF or HEVC format, and only when using iOS 11 or later.
All new photos and videos will now use JPEG or H. 264 format.
Convert your HEIC image to JPG
Broadly, any device or software related to Microsoft Windows do not accept HEIC files.
However there are a number of ways to convert an HEIC file to JPG, depending on what device you want to upload to. It's best to Google a solution for your device and operating system.
Educa and HEIC
We are working on a way to accept HEIC files and will make announcement when that solution is available to users.