Welcome to the Atlassian community! In order to add a custom field, you can follow the guides in the links below. Not sure if you use CLoud version or Server, so I included both. Let us know if you have any other questions.
Add a field on server version: https://confluence.atlassian.com/adminjiraserver/adding-a-custom-field-938847222.html
Add a field on cloud version: https://confluence.atlassian.com/adminjiracloud/adding-editing-and-deleting-a-custom-field-776636410.html
Does this answer your question?
Hey there Cloud Community members! We’re excited to give you the first glimpse of the new home for business teams on Jira — Jira Work Management. Jira Work Management is the next generation of J...
Connect with like-minded Atlassian users at free events near you!Find an event
Connect with like-minded Atlassian users at free events near you!
Unfortunately there are no Community Events near you at the moment.Host an event
You're one step closer to meeting fellow Atlassian users at your local event. Learn more about Community Events