Raka'ah is a special way that Muslims pray. Imagine you are playing a game with your friends where you have to do different actions. When you play this game, do you do the same action over and over again? That's what Muslims do when they pray. They do the same action called a raka'ah, which is like one round of the game.
Here's how it works: first, Muslims stand up straight and say some special words to begin the raka'ah. Then they bow down and touch their knees with their hands. This is called a ruku. After that, they stand up straight again and say some more special words. Then they go down on their knees and touch their forehead to the ground. This is called a sujud. They do this twice in every raka'ah.
When they finish one raka'ah, Muslims stand up straight again and start another raka'ah. They do this until they complete their prayer. The number of raka'ahs they need to perform depends on the time of day and the type of prayer they are doing.
So to sum it up, Muslims perform raka'ah as a way of praying to Allah. It involves standing, bowing, and touching the ground, and they do it over and over again until their prayer is complete.