i will do as:
If I had been already in contact with someone in the Office (and thus know his/her name), I will use " Dear ABC,"
If it is the first time, or it is to a Office email (e.g. admissionoffice@university.edu), I will use "Dear Sir/Madam"
I dont think it is really necessary to include the job title in the email, unless that's a prestigious one like Dr. / Prof.
Dear Mr. / Mrs. / Ms. XYZ will be enough.