How to get, enchant:
1. greatly enchanted ring of magic (its become from enchanted magic ring? if yes how to get it)
2. ennobled legendary golden ring (wiki says that legendary golden ring is dropped by Zor'Varuk, Mortie, but what next?)

What is maximum stats of those rings on legendary tier?
Thanks for answer.

Greatly Rings - obtainable from a quest, unrelated to the simple enchanted ones (+2 melee/ distance/ml), another quest and items.
Ennobled Legendary golden ring - you need to craft it with npc Frederik on Bersund (you need a legendary golden ring + 25 goldstones -> looted by monsters or daily quest gulshan village - npc Nathanael)

Extra max stats you can get from enchantment (legendary tier) -

+6 melee, distance or magic level
+5% critical hit boost
+5% hp steal
And 15 mana

Of course, besides their basic stats (+3 melee/+3distance/+3 ml - greatly rings or ennobled rings +2% mr)