Depends what you want to do, If you are a receptionist or a kennel attendant you will most likely be trained on the job. Vet techs go to school from 2 - 6 years getting an associates, bachelors, or masters (only reason to get a masters is it helps you get into vet school), when they graduate they sit for a state licensing exam. Vet assistants are usually trained on the job and mostly handle the pets and assist technicians.
By the way good luck on the new job
Please dont mind my spelling I am on my new Iphone and havent figured it out yet lol