What makes a contract null and void?

A plethora of things can make a contract null and void:

• It doesn't respect the 4 conditions for it to be enforceable: A contract, regardless of whether it's handwritten or not, needs to tick the the following boxes: A) Mutually agreed by both parties, B) Have legal validity, C) Capacity, D) Consideration.
• It's been tampered with
• It's been damaged
• It's been created by a party that was under the influence
• It's been created by a party that doesn't have the mental facilities
• It presents mistakes
• It presents terms that were violated by any party
• It presents information or data that is misrepresented