We've rounded up 4 unique methods for writing proposal submission emails. Plus, we've got email samples for each method.A business proposal email is a persuasive sales document sent to clients to gain business. Learning how to write an effective business proposal is essential. This proposal email template is designed for impressing clients with your achievements, social proof, or positive testimonials. Learn how to craft an effective business proposal email with our comprehensive guide. Us with the RFP number and title in the subject line. Use our business proposal email template to win clients faster than you can imagine. This is the easiest way you can write a business proposal email. An email request for the complete RFP form may be sent to the Contract.