Could anyone explain to me what these anchor strings, units and tab label is for in DocuSign

Hey so this is the scenario I am dealing with.

So I am sending leads document to sign and I want to add the date signed in a particular position in the document.
I added the “sign here tab” by specifying the location like this

I couldn’t do it like that for data signed, but instead its asking me for string and stuff, here is the screenshot

I come from a non-programing background so could anyone tell me what these are and how I could add the date signed tab in the document

Seems like the docs for docusign need an update. Without the tabs explanation hard to know exactly what this is for.

It is likely the app was updated but the docs were not.