Your booking confirmation email will include a detailed checklist of everything you need to bring when dropping off your dog. The main items are:
their food and any treats you give them
food bowls
any medications they need
their collar/harness and lead(s)
their bedding and/or crate if you use one
their favorite toys and items that will provide them with comfort
"poop" bags
dog towels
dog coats/jackets (if used)
Also, please don't forget your Carer's Fee!