Proceed with the following steps to add help tips to a custom field:

1. Log into Jira with a user that has a Jira administrator's permission.
2. Navigate to Administration > Issues > Custom Fields.
3. Click on the Edit link for the custom field.
4. Enter the following HTML snippet into the Description text box, and click on Update. You might want to substitute the href value to a real page containing help text:

        Need help to work out assignment? 
        <a class="help-lnk" href="/secure/ShowConstantsHelp.jspa?decorator=popup#Teams" 
        data-helplink="local" target="_blank"> 
          <span class="aui-icon aui-icon-small aui-iconfont-help"></span> 
        </a>

The following screenshot shows our new help icon:

We will now go through how these steps work.