There are 4 common uses of commas.

1. Commas can be used to break a long sentence into its natural parts.

A sentence containing three or more commas is likely to be too complicated, and should be restructured into two shorter sentences.

2. Commas can be used in place of brackets to enclose a phrase within a sentence.

The tender, which was worth £50,000, was submitted on time.

3. A comma can be used after an introductory clause.

If you are writing a report, check your punctuation and spelling carefully.

4. Commas can be used between the items in a list.

The bid team comprised John, Clare, Susan and Paul.