Column formatting given value

[TeresaJL]

I have created a meta-data column in SharePoint called "Issuer" and I also have a std column "Created by". Most of the time the Issuer is the same person who also created the document. 

Is there a way so that I automatically can get the name of the person who created the document in the Issuer column? Like a given value that you can change if you want. 

Regards,
Teresa

[#2]

Ok so I found something called "Default value" in settings. But this is not available when the column type is a "Person or group". Is there a way around this??