If you are looking for Triss after you first meet her in Novigrad you won’t be able to find her. Don’t worry, as you go through the story quests in Novigrad you will meet her again and eventually you get a side quest to help her out where you go to meet her at her hideout. This is where you meet Triss:
Triss Location Novigrad Witcher 3 Wild Hunt
auluftwaffles.com, short video game guides 
Ugh thank you so much! I had been wandering around Novigrad for nearly an hour trying to find “the bits” where she said her house was. Was driving me crazy! thank you!