It's all a matter of style and consistency. Some choose to capitalize only the first word, e.g. (using your example) The title of this question. Others capitalize the key parts of speech in the title, excluding conjunctions, prepositions, and the like: The Title of T/this Question. In some cases, all the words in the title are capitalized:
How to Reply to Confirm an Interview. When confirming a job interview, type a one-page letter thanking the interviewer for the invitation to the job interview. Confirm the exact time, date and location of the interview to avoid arriving at the wrong location on the wrong day or time. Send the letter within 24 to 48 hours of receiving the invitation. (Creatas Images/Creatas/Getty Images)
To receive a confirmation and reminder of your appointment, an e-mail address or cell phone number with texting is required. You can schedule, reschedule, cancel or verify a road test appointment through this online system. To reschedule, access the online system at the link below to look for another appointment. Your current appointment will not be canceled until you confirm your new appointment.