What is the purpose of a return postcard when filing a patent application?

A return postcard serves as prima facie evidence of receipt by the USPTO of all items listed on the postcard. It should include detailed identifying information such as:

• Inventor’s name
• Application number (if known)
• Confirmation number (if known)
• Filing date
• Title of the invention
• Type of paper being filed
• Number of pages for each component

The MPEP states: ‘A postcard receipt which itemizes and properly identifies the items which are being filed serves as prima facie evidence of receipt in the USPTO of all the items listed thereon on the date stamped thereon by the USPTO.’ (MPEP 503)