Spend time with your child practising writing their own name. We use cursive writing in school so see the video below for correct cursive letter formation for each letter of your child's name. Begin by writing your child's name on a line draw on a piece of paper. Check that they can identify that it is their name. Say the name of each letter in their name and point out how names begin with capital letters. You should write your child's name with a capital letter at the beginning and then lower case letters.
You can start by letting your child trace over your writing to get the feel and flow of each letter and gradually encourage them to write the letters themselves. Your child should be encouraged to hold their pencil with a tripod grip between the thumb and first finger, resting the pencil on the second finger in whichever hand feels most comfortable to them.