We are planning to create custom fields in JIRA and to link our instance to other software. Do you have any documentation/information that could be of use for us?
The following links could be helpful to you:https://confluence.atlassian.com/display/AdminJIRAServer071/Adding+a+custom+fieldhttps://confluence.atlassian.com/adminjiraserver071/configuring-a-custom-field-802592532.htmlhttps://confluence.atlassian.com/jira064/adding-a-custom-field-720412132.htmlhttps://confluence.atlassian.com/adminjiracloud/adding-editing-and-deleting-a-custom-field-776636410.html
Always ensure you've selected the correct documentatiaon for your JIRA version. You can do this in the drop down menu, in the top right corner on each page.