Is there a way in php to send emails without having to use the "mailto:" ?
Most everything I have seen uses this method, but a lot of people don't use MS Outlook.
The use of "mailto:" is not related to Outlook. On a Windows machine it will open the default mail program. That can be Outlook but also Thunderbird or any other.
On my Linux system it always opens Thunderbird.
As PsychicTide already wrote, using a form and sending the data with the mail() function is a much better method.
It avoids the opening of a mail program (and not every computer has one installed) and it hides the mail address for those systems that collect mail addresses to bombard you with spam.