According to the definition on deaffriendly.com:
"Ah, deaf-initions. Deaf-friendliness can mean different things to different people. Some perceive it emotionally, such as effortless empathy from hearing people who intuitively know how to meet our needs. Others see it as a technologically, such as an apartment retrofitted with blinking strobe lights – or a theatre with subtitle glasses or Rear Window® captioning." (2019)
"As a bare minimum, deaf-friendliness includes eye contact, clear speech, willingness to use pen and paper, and tons of patience. Whatever individual perceptions are, deaf-friendliness is not something businesses can afford to skimp on." -- https://deaffriendly.freshdesk.com/support/solutions/articles/6000039887-what-do-you-mean-deaf-friendly-
In 2019, Detla was the first U.S. airline to provide a sign language tag to qualified employees. It includes ASL and over 300 signed languages around the world. [Ref]
For a general or everyday customer service, meet a deaf person's preference of communication. Find out what they use or prefer (e.g. writing/typing or lipreading/speaking). If you know some ASL, fabulous!
Interpreting is used in legal, medical, and educational settings as well as meetings.
For contact or communication via phone, offer a Deaf person a mobile text number. Even if a company, school, or admin office doesn't offer a mobile text number, often a clerk/salesperson/secretary/crew voluntarily offers their personal mobile number for appointments, service-related contact, or such, just for a Deaf person.
For a hotel room, accessible design standards are required by the ADA (American with Disabilities Act) in the U.S. Check ADA for information on accessibility requirements.
In a waiting room (e.g. doctor's or dentist's office), leave TV closed-captioning on. Likewise, in pubs. Hearing viewers also enjoy it.