Facebook has decided to restrict the design of the preview of links. The title, description and image of the preview can therefore no longer be edited for any link. There is an exception only for links that lead to your own website. You can find more information about this in the help section of Facebook: Edit-Link Preview
To be able to edit at least the preview of your own links, you need to confirm the ownership of a page on Facebook. This is a bit more complicated, and it may be that - at least partially - one of your colleagues from the IT department has to help. Facebook describes what exactly needs to be done in an article in the Developer section: Domain Verification
To enable link preview editing in SocialHub, this meta tag should be added to the HTML source code of the web page in addition to the domain confirmation:
<meta property="fb:pages" content="[ID der eigenen Facebook-Seite (kommagetrennte Liste, wenn es mehrere Facebook-Seiten gibt)]">
As soon as this is done, the options of the link preview are automatically activated in the SocialHub for you to edit. You can create a link post by clicking the third icon (marked yellow in the screenshot) and then entering the address in the "Link URL" field that appears below it: