To get the HM Strength in Pokemon Red you need to do a little side quest. This quest involves finding the Safari Zone Warden's missing Gold Teeth which can be found in Area 3 of the Safari Zone itself. After finding the Gold Teeth and bringing them back to the warden he will give you the HM for Strength.
Strength
you use strength
you cannot rent any Pokemon in red version
It's in safari park.. right in front of the house where u get Surf
rock smash isn't in Pokemon red version
let all you're Pokemon faint and you'll return to the last Pokemon center you used.
No
You can't, you can only do that on Pokemon yellow version
Red version was not made to migrate with emerald.
No!
A modified version of Pokemon Red.
No