Automatic numbering using company prefix

I would like the PO, SO, SQ, SI to have automatic sequence numbering using our company prefix at the beginning.
how can I do that?


The only way you could do this is with a custom theme inserting your prefix ahead of Manager’s automatic reference number.

sorry, I don’t catch what you mean.
is there any link guiding to what you indicated?

Look at the Guides related to themes. There is a category for themes, and the Search function works quite well.