Jiggly puff does not evolve at a level, but by using the moonstone.
In route 3 in the grass there are Jiggly Puffs
no its a regular Pokemon like a meowth
Route112
Route 115
sing
yes
by breedeing two jiggly puffs
You use a Moon Stone.
it evolves to jiggly puff
according to the official player's guide for Pokemon emerald version wild lunatone is the only Pokemon that hold moon stones and they can't be caught in emerald. You need to trade a lunatone over from sapphire.
You might find it in the Trophy Garden if that is the Pokemon of the day.