Reading is a vital skill that needs to be practiced. Please buy or borrow kindergarten and grade 1 level books for your child to read to you. They should be stories with 1-2 sentences on each page.
I strongly encourage parents to buy levelled readers from scholastics or other stores to practice reading with your child over the summer. The stronger their reading skills the easier the transition will be to grade 1.
When your child is stuck on a word help them learn strategies for figuring the word out: look at the pictures, sound out the word, break the word up into smaller bits they know, rereading to make sure what they are reading sounds right etc.
Reading level appropriate books over the summer will boost their confidence in their own abilities!