CVC words are made up of a Consonant, a Vowel and a Consonant. Some examples are:
hat, men, din, fog and pup.
It is important for children to learn to read and write CVC words early on. They usually begin sounding them out when they read and write them, but the aim is for them to be able to look at these words and recognise them immediately without thinking about them.
'at' words are a good place to start as most children who can read at all can read and write the word 'cat'.
Ask them to write cat. Then ask them to write rat underneath. If they can't, spell it out for them. Point out the at endings in both words. Most children aged 6 or more with a reading problem are then able to write quite a few at words when asked.
Continue this in following lessons with different rhyming CVC words, always practicing what has been learned previously.
You can find some free printable CVC word lists here. There are some longer words listed as well. Introduce the 3 letter words first.
A great package entitled Short Vowels can be bought and downloaded at Teachers Pay Teachers. You can find it here.
If you Google 'CVC words' under Images you will find a wealth of information and relevant activities,ideas and word lists.