Half-day excursion
The listing says 6 hours departing from Cusco. It includes hotel pickup, drop-off in central Cusco, transport by air-conditioned vehicle and a guide. Admission to Moray and Maras is paid separately and only in Peruvian soles, so bring cash. It is the option if your only plan for the day is these two sites.
Sacred Valley in one day
The listing says 12 hrs 30 min, with transport by minibus or bus, a buffet lunch and a guide. Hotel pickup depends on the option. Besides Moray and Maras, it includes Ollantaytambo and Pisac, which have their own pages. It works if you only have one day for the valley.
What you pay separately
On the one-day Sacred Valley, the listing leaves out the partial tourist ticket, admission to the Maras salt mines and drinks. On the half-day excursion, admission to Moray and Maras. Have cash ready and check how the tourist ticket works on its page before you set out.
How to choose
Choose the half day if you want to go at an easy pace and be back in Cusco early, and the one-day tour if you prefer to see more sites in the valley in a single trip. If you have already booked Machu Picchu, keep this tour for another day of your trip and check the guide's language on the tour listing.