So alongside my house they are building a building so they had to do some excavation and left a deep (hole?). Im not sure if hole is the correct term and right now they are people there so i wasn’t sure if saying “oh look there’s people in the hole” is correct
As you indicated, I would call it an excavation:
- a hole or hollow made by excavating.
Look, there are some people in the excavation.
Informally, you could also call it a "hole in the ground".
A hole is fine, though without context it could be man-made or otherwise. So for clarity, I would simply add that it is a "hole for a building foundation".
Excavation would also be good as @user3169 mentions, though the first thing that comes to mind is a archeological dig, as in digging into the ground to uncover or reveal, which isn't quite the case here. Still, it makes it clear that it is a man-made hole.