Your recipient opens the link in any browser. They do not need a FlipperForce account, they do not need to log in, and they do not count against your workspace user seats.
The page shows the update text and the photos you attached.
The photos are interactive rather than a flat report. Clicking any thumbnail opens the image at full size, and from there your recipient can scroll straight through the rest of the photos as a gallery. This matters when the photos are the point of the update, like a lender verifying completed work before releasing a draw.
Your recipient can view the update. They cannot edit it, comment on it, or see anything else in your workspace.
Read the full article: What does someone see when I send them a Project Update share link?