Hello, Altavia!

Thank you for your question.

I can see two scenarios here:

1 - Let's assume you have a many2one field on the model Z to the model X: in that case you can set up a related field to get the field you created (on Z) on X.

2 - What are the 'Existing Fields'? those are fields that are on the current model and not in the view, invisible or not.

I hope I helped!

And to know more about Studio and other Odoo applications, you can schedule a demo with an Odoo Expert: https://www.odoo.com/r/w2t :)

Cheers,

Odoo eLearning Team.