Us standard date format.

I want to set the US standard date format for email notifications. For example:

Dear CLIENT,

We would like to inform you that your appointment with SITE_NAME on DATE_TIME has been removed.

Requested service: SERVICE
Date and time: DATE_TIME

SITE_NAME

This is the default I just want to set date as MM-DD-YYYY.

What should I write instead of DATE_TIME.

Please check and help.