Okay, you dont need to call it vacuum if that confuses you. Call it 0 psi.
Imagine a tall cylinder, open top. Do you agree that the pressure in the cylinder will be greater at the bottom of the cylinder than at the top? This is because air has weight, like every other material. Wait though, why doesnt the air get sucked out the top of the container? Considering the air at the top is at a lower psi than the air at the bottom of the container.
Okay, you dont need to call it vacuum if that confuses you. Call it 0 psi. Imagine a tall cylinder, open top. Do you agree that the pressure in the cylinder will be greater at the bottom of the cylinder than at the top? This is because air has weight, like every other material. Wait though, why doesnt the air get sucked out the top of the container? Considering the air at the top is at a lower psi than the air at the bottom of the container.