In a regular scenario, when a Collaboration Link is created to an artifact in a remote application, a backlink is also created in the remote application back to the Jira issue. If the remote application has registered Jira as friend, it is possible to get a preview of the Jira issue by hovering the backlink . This Issue preview contains the following Issue fields by default:
By setting this configuration, you can extend the preview information by including more fields. The only thing you need to do is to create a custom Jira screen with the extra fields you want to include and then associate it with an Issue Type Scheme. This way all issues of all projects using such scheme will use the extended preview. You can go even further and define custom previews for the Issue Types within the scheme, screens defined at the Issue Type level will override then the one defined at the scheme level, if any.
It is worth to mention that all tabs defined on the screen will be considered to create fields sections (named as the corresponding tabs) where the fields will be grouped in. Fields sections will be arranged on the preview in a two-per-line fashion, keeping the same order in which they were defined on the screen.
Once the Jira screen has been defined:
JIRA ADMINISTRATION > Manage appspage.
Issue Previewsoption in the
Scheme Screencombo and select the chosen screen to expand the corresponding previews. 
To customize the scheme screen at Issue Type level:
Customizelink located in the second column.
To restore the scheme screen at Issue Type level:
Restorebutton located in the second column.