How do farmers get water from their fields?

through irrigation which can be from a well or and they pipe all the water to the fields or center pivot irrigation where a portable irrigation pipe about 100m goes around circular fields and sprays water on crops and rotates really slowly. also any bodies of water such as streams or rivers through permission from the owner such as the government, then when permission is accepted then you pump water to your fields. Also when it rains it automatically quenches crops.