Learning to read is a complicated task. If children have to sound out every word, it becomes so laborious and slow that children might want to give up, or if not, they will have a difficult time comprehending what they are reading. Many words that are used frequently are impossible to sound out, so they must be learned by sight.
Learning high frequency words by sight helps children build confidence and fluency in their reading. Reading becomes easier and makes more sense.
Your child may bring home flashcards from school. Take a few minutes to practice them each night. Make a second set and play a game of concentration, making sure that your child reads the words before picking up the matching pairs.
The following link has printable sight word flashcards.
https://sightwords.com/sight-words/flash-cards/
Play online games with sight words
https://www.roomrecess.com/mobile/SightWordSmash/play.html
https://www.fun4thebrain.com/English/popcornWords.html
https://mrnussbaum.com/sight-words-audible-online