A colon is a punctuation mark. It looks like this :

A colon is often used at the beginning of a list of bullet points - like on a shopping list!

It can also be used in some other types of list, but not all lists.

The first of the following sentences needs a colon, but the second does not.

These are the people I am inviting to my party: Kate, Joe, Adil, Dwayne and Jamila.

I am inviting Kate, Joe, Adil, Dwayne and Jamila to my party.

So how can we decide whether we need a colon or not?

If the section of the sentence before the colon makes sense on its own, then we use a colon.

'These are the people I am inviting to my party' makes sense on its own.

If it doesn't make sense on its own, we don't use a colon.

 'I am inviting' does not make sense on its own.

Let's see if we can put this into practice!