what were medieval knight’s roles in medieval society?

During the Middle Ages, Western Europe came under attack from many outside groups. These attacks came from groups like the Magyars in Eastern Europe, the Vikings in Northern Europe, and Muslims from North Africa. Due to these attacks, people in Western Europe lived in fear and sought safety within their communities. This led to a shift in society from being focused around a strong centralized government to smaller, local government entities. This system became known as feudalism.
In the feudalism system, a king would divide his territory into smaller pieces known as fiefs. Each fief would be granted to a noble who would promise loyalty to the king response for the land. This meant that if a threat came, the nobles would come to the defense of the king. They would be responsible for providing soldiers to build a force for the king to fight off the invaders. Additionally, the nobles would often be responsible for providing the king with taxes.
The nobles who received land from the kings often were knights. Knights were warriors who held a higher military status than the peasants who made up the bulk of the force. Knights were typically heavily armored and well-trained. Due to this, knights commanded a great deal of respect from their enemies on the battlefield.
https://www.metmuseum.org/toah/hd/feud/hd_feud.htm