As you talk to your child about their drawings or the words and letters they have created they are beginning to understand that there is a connection between talking, writing and reading.
When children have plenty of opportunities to draw and write they are practising the skills they need to become skilled at writing.
They will also be learning that words and pictures have meaning and that the meaning is constant. If your child writes a word that you can read - like their name - they will learn that those letters together will always make that word.
When they draw a picture and they can describe it to you they are reading the picture - this is good practice for reading words.