Geraintm6

Hi, not sure if ive posted this in the right section, but im making a website thats mainly html but ive thrown some PHP for the contact us page, i have used a form that requires the user to send a message to an email, ive tested it and i get the message that ive set to show that its sucessfully sent, but when i check my email to see if it has sent well... it hasn't, im new to PHP but do i have to have the site online in order for the message to send?