Is Felidar Umbra legal in Standard, Modern, and Commander?

Felidar Umbra is legal in: Legacy, Vintage, Commander.

What type of card is Felidar Umbra?

Felidar Umbra is an Enchantment — Aura. Its oracle text reads: "Enchant creature Enchanted creature has lifelink. {1}{W}: Attach this Aura to target creature you control. Umbra armor (If enchanted creature would be destroyed, instead remove all damage from it and destroy this Aura.)"