Custom invoice pdf - I want to add some fields such as "Primary contact name"

[Yramgar]

I am customizing the pdf template (html,css and php) and I would like to print the variables in the "Basic info" tab, so that they are printed in the pdf. Does anyone know how to do it or how do I call these variables? I don't see them in the documentation

Display Name
Primary contact name
Email
Prefix
Pone
Website