Since version 8.16 of Jira Data Center administrators can set a default value on the Description field per project. You can learn more about it how it works here.

We would really appreciate your comments and feedback on the released capabilities. We would love to hear also what are the most important features that you would like to be added to Jira Data Center for Default Values of System Fields.

Thank you,
Grażyna Kaszkur
Product Manager, Jira Server and Data Center