When I click "Save" or "Save As" in Illustrator, I don't see PNG as an option.
In some versions of Adobe Illustrator, you'll find the PNG option in different spots. Try these methods:
Method 1:
File > Export > Export As (and choose PNG as your Format in the drop down menu)
Method 2:
File > Save for Web and Devices
Method 3:
File > Export > Export for Screens
Tip: If all else fails, just take a photo of your screen and share that with us in the Facebook group -- the only reason we want a PNG is to see your awesome work!