To use the php mail() function, use the following syntax: 

mail(to,subject,message,headers,parameters);

• to: This is required and says who will be receiving the email
  
• subject: This is required and specifies the subject of the email
• message: This is required and gives the message to be sent, with a maximum of 70 characters
• headers: This is optional and includes fields such as from, cc, and bcc.
• parameters: This is optional and includes any additional information

If this is your first time setting up php mail() function, we recommend reading the official documentation on using this code as it also includes examples.