Can I make a custom field that replicates description/comment field?

[Stephen Brenish]

I want to be able to create a custom field that has the same ability as a Description/Comment field does.  More or less I would like the content editor to be useable in a custom field.

I have already enabled Wiki Markup but I want to be able to make external links etc in this field similar to the way I am able to do that in the description/comment field.  Is this functionality available?

[AgentSmith]

Its not possible in JIRA Cloud. You might want to explore JIRA Server, which can leverage script runner:

https://marketplace.atlassian.com/plugins/com.onresolve.jira.groovy.groovyrunner