Maintenance for the week of March 25:
• [COMPLETE] ESO Store and Account System for maintenance – March 28, 9:00AM EDT (13:00 UTC) - 12:00PM EDT (16:00 UTC)
1. You can get this invitation from another character after leveling him to lvl 45
2. Though it should be possible to take Undauted quest without invitation. Try to talk to NPCs at any undaunted base in a capital city