I agree with esmr2d2 because 'if' has several uses. I will explain its important use.
‘If’ implies a condition on which something depends and is primarily used as a conjunction to introduce a clause that indicates suppositions or hypothetical conditions (often involving doubt or uncertainty); see examples below: § In the event that: If I were to go, I would be late. § Granting that: If that is true, what should we do? § On the condition that: She will play the piano only if she is paid. § Whether: Ask if he plans to come to the meeting. § Hypothetical condition: If I were the President, Iwoulddeclare war against terrorism.