Is there a common essay on the common application?

Hello!  Sorry for the delayed response.  I've been in China!  Yes, there are common question(s) on the Common Application. Schools will vary in the number they want you to respond to.  You can view the 2017-2018 questions using the link below.  In addition, specific schools may require the student to answer supplemental essays.  You will find these requirements within the Common Application when you select specific schools.  Hope this answered your question.  
Best regards,
Dr. Avonna Swartz 

http://www.commonapp.org