Looking at the eclipsed sun, even briefly, without appropriate eyewear can permanently damage the retina.
Watching an eclipse through a phone camera can both damage the mobile's lens and your eyes. To click a picture, make sure to use a solar filter.
You should avoid looking at the eclipse bare eyed even for a second or two.
Even during a partial or annular eclipse, the Sun will still be very bright, warns NASA. The American space agency warns that those watching an entire eclipse, may be in direct sunlight for hours and must remember to wear sunscreen, a hat, and protective clothing to prevent skin damage.