The Americans with Disabilities Act (ADA) protects people with disabilities from discrimination.  See below for info about service animals and emotional support animals. There is no official registry for service animals or emotional support animals, but some businesses, etc may request a letter explaining why an emotional support animal is needed.

California law allows persons with disabilities to bring trained service dogs and psychiatric service dogs, but not emotional support animals, to all public places.

Service Animals are:

• Dogs
• Any breed and any size of dog
• Trained to perform a task directly related to a person’s disability

Service animals are not:

• Required to be certified or go through a professional training program
• Required to wear a vest or other ID that indicates they’re a service dog
• Emotional support or comfort dogs, because providing emotional support or comfort is not a task related to a person’s disability

A public place can ask only two questions to determine if a person's dog is a service dog:

• whether the dog is required because of a disability
• what work the dog is trained to perform

NOTE: Religious entities are completely exempt from Title III of the ADA. All of their facilities, programs, and activities, whether they are religious or secular in nature, are exempt. 

Emotional Support Animals (ESAs), also known as Comfort Animals, have no specific legal definition and there is no official registry for ESAs. Individuals who travel with emotional support animals or psychiatric service animals may need to provide specific documentation to establish that they have a disability and the reason the animal must travel with them. Individuals who wish to travel with their emotional support or psychiatric animals should contact the airline ahead of time to find out what kind of documentation is required. Examples of documentation that may be requested by the airline: Current documentation (not more than one year old) on letterhead from a licensed mental health professional stating (1) the passenger has a mental health-related disability listed in the Diagnostic and Statistical Manual of Mental Disorders (DSM IV); (2) having the animal accompany the passenger is necessary to the passenger’s mental health or treatment; (3) the individual providing the assessment of the passenger is a licensed mental health professional and the passenger is under his or her professional care; and (4) the date and type of the mental health professional’s license and the state or other jurisdiction in which it was issued. This documentation may be required as a condition of permitting the animal to accompany the passenger in the cabin.
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Web pages

• Frequently Asked Questions about Service Animals and the ADA - https://www.ada.gov/regs2010/service_animal_qa.html
• Service Animal info  - https://beta.ada.gov/topics/service-animals/
• California Laws on Psychiatric Service Dogs and Emotional Support Animals in Public Places, including definition of Service Dog - https://www.nolo.com/legal-encyclopedia/california-laws-psychiatric-service-dogs-emotional-support-animals-public-places.html
• Service Animals and Emotional Support Animals - https://adata.org/guide/service-animals-and-emotional-support-animals?utm_source=ADA%20Center%20Service%20animal%20booklet%20announcement&utm_campaign=SVC%20Animal%20booklet&utm_medium=email
• County of Placer info about Service Animals (links to Department of Justice/ADA documents) - https://www.placer.ca.gov/5784/Service-Animals Links to: https://www.ada.gov/regs2010/service_animal_qa.html and https://www.ada.gov/service_animals_2010.htm#:~:text=A%20service%20animal%20is%20a,public%20are%20allowed%20to%20go.
• Info about letters for Emotional Support Animals (ESAs) - https://www.certapet.com/emotional-support-animal/. This resource is provided for info only and is not an endorsement for professional services.
• Religious entities are exempt from ADA Title III of the ADA. Religious entities include places of worship, such as mosques, synagogues, and churches. Additionally, other places or programs controlled by religious entities (such as schools, hospitals, day care centers, adoption agencies, thrift shops, shelters, and food banks), are also considered religious entities. - https://adata.org/factsheet/religious-entities-under-americans-disabilities-act#:~:text=No%2C%20religious%20entities%20are%20completely,secular%20in%20nature%2C%20are%20exempt.