There are 5 Hermit Locations in Assassin's Creed Origins. Finding all Hermit locations unlocks the Words of Wisdom Trophy / Achievement.

These also give you 1 ability point each. It's a quick way to gain ability points early in the game.
The first chance to do this is after doing the Siwa main quests (starting area). After this, the entire map opens up for free roam. You can still do it after the story.

The hermit locations have a rug you can interact with. Scan the area by holding D-Pad Up to find the carpet more easily. You must interact with the carpet (press Triangle on PS4 / Y on Xbox One) to make it count.

They actually show up on the map as question marks after synchronizing the nearest viewpoint. This makes them a bit easier to find. If you have trouble finding the exact spot in one region, be sure to sync the viewpoint and go to the question mark displayed on the world map.