I have been teaching a class on learning to read tarot for others. One of the things that comes up for many newbies is, "Should I get certified or join a group?" I have been reading tarot for over 30 years. I began to study on my own out of curiosity. I lived n a small town in Iowa and there were no classes and this was BEFORE the internet! I read for friends only. After five years, I moved to Miami and was fortunate to meek the creator of my deck, The Voyager. I went to a New Life Expo to hear Dr. James Wanless speak. He was just developing a certification course. I have spent the next 10 years taking courses and learning to teach as well as enhance my skills.
Several associations have formed over the years to support tarot readers. However, the most successful has been the Tarot Association out of Keswick England. It's tag line is "Restoring the dignity of tarot". The leaders, Marcus Katz and Tali Goodwin, have dedicated themselves to exploring the history and future of tarot and divination tools. They are prolific writers as well. You ay find their many books on Amazon (many on kindle). I highly recommend their "Secrets of the Rider-Waite" for a full history of the classic deck.
Joining the Association provides me with access to many free videos, guest speakers on webinars and access to other tarot readers worldwide. The Association also sponsors several conferences worldwide. Well worth the $85 per year fee. You even get a free tarot deck when you renew your membership. Sign up at TarotAssociation.net.