You can also use a comma to:

• Separate a city or town from a state or province, as in Sarasota, Florida and Ferntree Gully, Victoria.
• Set off the name in a direct address, as in, “Jane, can I please see you in my office?”
• After dates, when day, month, and year are used, as in, “He was born Thursday, August 12th, 1975.”
• Before degrees that come after a name, as in Joan Walker, PhD.
• Set off an informal quotation, as in: Robert remarked, “My investment counselor is very good.”
• After linking adverbs such as however, therefore, etc. “The hike was several miles long; however, the path was a good one.”
• Separate thousands in numbers for clarification, as in 18,239.

NOTE: Not all countries use commas and periods in the same way or for numbers over a thousand or decimals. Make sure you know your audience!