icefall cave
The short answer is no. There is no Dive, HM 08, in Pokemon FireRed.
Their are 7 HM's available in Firered.
You cannot get it in Pokemon FireRed. It doesn't matter because it is not necessary in Pokemon FireRed.
Where did you hear that? There is no such HM as remover in any game.
At rt 2.
waterfall
pour water on your game
HM 8 doesn't exist in Pokemon Fire Red or Leaf Green.
Celadon City
Either by using the HM Strength or by using the HM Rock Smash
Use the HM move Strength.
You need to learn the HM strength.