The moment of totality during a total solar eclipse is the only time it is safe to look directly at the sun without appropriate eyewear. In the moments leading up to, and following totality, it is important to wear only specialized “eclipse glasses.” Sunglasses ARE NOT safe enough to use during a solar eclipse.
The American Astrological Society has a dedicated list of trusted and certified producers of eclipse eyewear that is needed during an eclipse.
It is also unsafe to look at the eclipse through a telescope, camera, or binoculars without proper filters or adapters. There are several other indirect methods for looking at an eclipse if eclipse glasses aren’t your thing.