How can I customize auto responder emails

I need to send different text based on an answer to one of the fields in my form. How can I customize the email with some conditions, so that based on the drop down selection in a form, it sends a certain email over another?

Please refer to the user guide: 

https://www.jotform.com/help/167-How-to-send-to-a-specific-email-address-based-on-a-selection

What you will do is create multiple Autoresponder Email. You can do that using the Add New Email button in Email

Each Autoresponder Email contains different message body/template.

Then, create a condition base email to have rules which email(autoresponder) will be sent to the end user depending on what they answered/selected on the form.

Hope this help. Let us know if you need furhter assistance.