Is it possible to create a survey without intro or outro message?

No, both intro and outro messages are required for each survey.

The Intro message serves to provide survey recipients with the information necessary for them to make an informed choice on whether or not to participate in a survey. It is good practice to start with an Intro message and that's also why we require it as a standard for surveys.

The outro message, on the other hand, clearly signals to survey participants that the survey is finished. It also serves to show participants that their response has been received and recorded. Without receiving a response to their message, participants may be confused as to whether their answer has been registered.