mail function in php doesn't work in production code example
Example: mail function php not working
Although there are portions of this answer that apply to only to the usage of themail() function itself, many of these troubleshooting steps can be applied to any PHP mailing system.
There are a variety of reasons your script appears to not be sending emails. It's difficult to diagnose these things unless there is an obvious syntax error. Without one you need to run through the checklist below to find any potential pitfalls you may be encountering.