How to show more data in the link lookup area?

How do we control what data fields to show/hide in this link lookup?
Where to change the setting
Thank you

It’s the Naming Series. You can search for Naming Series and enter BOM and change the naming series to whatever you like, for example take out the BOM prefix. Or even better, you can go to Customize Form and enter how you would like to generate those “document” names.

I am unable to find BOM in the naming series
Am I doing something wrong?