My previous work included special characters such as heart, diamond, club and spade in test relating to bridge hands.. I just tried to update this work could not find an option to include these characters.

My system is Debian stretch running GIMP 2.8.18.The original work was done on 6/15/2015 so certainly a much older version of GIMP

You might have just caught a Gimp 2.6 with Debian 6 (EOL 2016), but that image has the blocks of text flattened to a bitmap - not really editable. There is also an active selection in your image that needs promoting to a layer, if you want to progress.

Adding the card symbols. Any number of ways: The linux orthodox way, using unicode U plus a character code.

see the attached file.

Other ways.

Do all your text in some other application such as LibreOffice which has a special symbol facility then copy/paste into the Gimp text tool.

Use a character map and copy/paste individual symbols into the Gimp text tool.

examples: https://i.imgur.com/zSuJxze.jpg

Then the quick-n-dirty way. Make brushes for the 4 shapes and paint in as a "stamp"

Thanks for a very helpful reply. LibreOffice is clearly best for this job. I might someday want to use unicode characters in a drawing but I can't open a text toolbox like the one in the example zSuJxze.jpg.