Due date should be Created date +30days

[Rasajna Meka]

Due date should be Created date +30days (calender Days)

[Jeroen Poismans]

Hi,

Easiest way to do this is with an automation rule triggering on Issue create. The as an action you would set due date to 

{{now.plusDays(30)}}

Here is some more info covering automation rules, smart values and Date manipulation:
https://support.atlassian.com/cloud-automation/docs/jira-smart-values-date-and-time

Let me know if this helps!

Regards,

Jeroen