If a student with a disability is registered for your class and is requesting an accommodation, they will provide you with a confidential accommodation approval letter. This letter will state in general terms that the student is connected with disability services and will list the appropriate accommodations that have been approved. This letter will not give any diagnostic information.
You must sign the accompanying "acknowledgment of class accommodations" form as verification of the student disclosure. The student is then responsible for returning this to disability services.
If a student approaches you about needing accommodations but does not have the letter, you should refer them to disability services immediately.
Faculty should not provide accommodations to coursework without disability services approval. To do so would leave the university and the individual faculty member open to potential legal difficulties.