Getting reputation with the Tortollan SeekersThe Tortollan Seekers are mainly a World Quest faction, so they don't really have their own quest line that gives you a starting point for the reputation. This means that you can begin to earn reputation at level 120 when the World Quests are unlocked.
The Tortollan Seekers World Quests are spread all over the six zones in Zandalar and Kul Tiras, and they give 75 reputation per completion. Just like the other factions, the Tortollan Seekers can be the daily Emissary faction, so completing 4 World Quests for them during this 72 hour period will give you an additional 1,500 reputation as well as a bag that can contain gear or other cool stuff.
There is a Contract available for the Tortollan Seekers called Contract: Tortollan Seekers, and you can use this to get 10 reputation each time you complete a World Quest, even if it's not related to this faction at all. Here's a guide to understanding the BfA reputation Contracts.
Occasionally you will get acess to a Tortollan Seekers mission on the Mission Table, and each of these will give you 150 reputation.