Greetings! I hope this email finds you well.
My name is [Insert Name]. I've been a [position] for about [duration] years and have [insert accomplishments] [example: oversee projects in major cities in the U.S. and Europe]. I'm very much interested in your project offer, and yes, I am willing to travel for an assignment.
I am attaching my resume for your consideration. My rate would be [Amount] per [duration] hour/project.
I would love to meet with you and personally, show you my portfolio.
Thank you very much,