Service Dog for current tenant and what to ask for legally

[Jeff Payne]

Hello everyone, one of my renters in a suburb of Phoenix, AZ asked me about 3 months(6 months into a 2 year lease) ago if they could get a dog(its agreed to by both parties no pets)and i said "sorry, no"..  Then last week she texted me quote.........."good afternoon, hope your having a good day. not trying to sound like a pest but the dog situation....im wanting one for a service dog for me..... i have anxiety and i would be able to train it for my needs. im stay at home mom now and would be with the dog 24/7. so you wouldnt have to worry about the house being destroyed. please think about it and let me know. Unquote

Any help would be greatly appreciated.  May I request a letter from her Dr. with permission from my tenant for me to follow up? Medication proof?  I dont want to do or say anything that will get me into trouble.  THANK YOU!!