How to sync photos to iCloud Drive?

Question

iPhone

In fact, a few questions about the newfangled iCloud Drive:
1. How can I see the files uploaded to iCloud Drive on the iPhone?
2. Can I use a subject to store photos (similar to iTunes Match, but for photos)? Space on the phone is sorely lacking. If possible, how?
3. If in paragraph 2 the answer is "impossible", then how can I transfer a photo from a subject to the phone's memory?
Thank you!

Answer 1

1. Through the interface of applications corresponding to file types.
2. To do this, there is a function " My Photo Stream ".