You must level it up with max happiness. To improve its happiness, you can give it a massage by someone in the Goldenrod Underground Tunnel. Winning battles helps too. If you have been there, Blue's sister in Pallet Town will give your Pokemon a massage from 3 pm to 4 pm (I think).
To evolve the Munchlax you just have to level it up when its holding the leftovers.
Snorlax does not evolve. However, he does evolve from Munchlax. There is no specific level that Munchlax evolves. If he levels up with a high happiness rating, he will evolve into Snorlax.
Catch a munchlax with sweet honey and then evolve it
It evolves via happiness
No, Sableye does not evolve.
raise its happyness to max
let munchlax evolve
It evovles with max happiness
You need to get it's friendship to full.
by leveling up to level 78
If you catch a Munchlax or Snorlax, they will have one. Otherwise, you can't get one.
Give it a full incense and breed it to get a Munchlax egg.