Can my customers ask for things like a late arrival or a quiet room when they book a hotel?

Yes, in most cases a customer can add a request such as a late arrival, a high floor, twin beds instead of a double or a quiet room, and it will travel with the booking to the property. The important thing to understand, and to say to your customer at the time, is that a request is not a guarantee. The hotel receives it as a note against the reservation and honours it only if it can on the day of arrival.

How much you are able to send depends on the supplier the rate came from. Some suppliers accept a free text note and pass it straight through to the hotel. Others accept only a short list of standard options, such as a non smoking room or an approximate arrival time, and anything outside that list is quietly dropped without an error. So the same wording can reach one hotel in full and never reach another at all.

Anything the guest genuinely must have, such as an accessible room, a cot for an infant or two rooms next to each other for a family, is safer handled by contacting the property directly once the booking is confirmed, with the confirmation reference to hand. That way you have an answer from the hotel itself rather than hoping a note was read at the right moment.

When you take a request from a customer, set the expectation in the same breath that it is a request and not a promise, then check the voucher once it is issued to see whether the note has actually carried through.