Am not a php programmer.
Setup you may need is using a SMTP(not sure if required for php).
You also need a domain name. Some hard email servers also accept emails were signed probably, otherwise they might ignore it or send it as spam.
Even if you don’t get any issue in local environment, the target might ignore the message.
Make sure you are sending from a domain you own, otherwise will fail(or worse, blacklisting).
Better way could using external API to send mails, not sue if available any, but one simple solution could be about google.