How to activate Custom Field in Supplier or Customer Statement?

I never try custom fields in statement I might miss out some step. Is there a guide for it?

Please do not use personal messages for general questions. I have moved yours to the public forum, where it can receive more attention.

The quote you attribute tome is actually a combination of a statement I made with a question I asked and an opinion I expressed. It creates the impression I am writing about a single thing, when I was not.

The first portion, including the hyperlink, was about using themes for statements. The second portion was a question trying to clarify what another forum member said about a problem with custom fields. The final sentence was the opinion about what might cause that problem. I don’t yet know the answer to the question because I have not tested it yet.

You cannot define custom fields for statements, so there is no Guide.

Well I ask of you because I doubt there is even possibility to do it. and yet there is user did it. This post not needed to be in public.