My ducks and geese free range daily from the time it is fully light till right before dusk. While it is dark/night, they are all locked up in predator proof housing (I do not put food or water in overnight with them...they make a mess). As Celtic said, they need pasture during the day, clean water to drink, and enough water to bathe in as well (not necessarily a pond...lots use small tubs or kiddie pools).
Only a few of my birds can fly a little (19 ducks and 16 geese). The best flyer on the property is Harriet, my 9 month old Toulouse goose: She can get 10 feet off the ground and fly several hundred feet. She has never left our property and prefers to stay with the flock she was raised with.
If you live in an area that gets a lot of winter snow and the grass dies, you will need to provide the geese with some sort of replacement: Many have been discussed on an older thread that can be found here....
https://www.backyardchickens.com/t/690124/drought-has-dried-up-all-my-grass-what-are-you-feeding
If you live more Southward (TX, LA, MS, AL, southern GA, FL...to name a few) you can grow annual rye grass during the winter for the geese. I throw in a few pounds of clover, alfalfa, chicory, and some oats and wheat seed too.
Good luck!