im new to Ragnarok and was wondering how are quests given in this game are they given by npc's or automatic by level thanks....

Quests are given by NPC's... but you do not need to talk to most of them in order to begin the quest...

All quests have requirements... such as Kaho-horns.
5emp
alot of items and
1 million zeny

if you have all of the requirements before talking to the NPC, you will be able to immediately hand in the quest.

How do i tell which npc's are quest npc's

Sometimes it can be hard to know which NPC's are quest NPC's and which NPC's are completely useless...

Thats up to you to find out..
Basic Quest:
Smiley mask at Kafra NPC