How do I make a field enabled in new mode, but only visible to certain groups in edit/display mode?

You can place a rule on the form control and hide it for users not in a specific SharePoint group using the formula below.

not(fn-IsMemberOfGroup("Your SharePoint Group Name"))

You can also mix in the "Is New Mode", "Is Edit Mode" and "Is Display Mode" options from the Common tab into the formula.

That doesn't work in this case.

I have 2 User Groups.  "Everyone" and "Managers."  PII field in question is "Account #"

When a User (Everyone) adds a new Item, I want them to have access to enter an Account #.  Once they save the Item, the Account # field will no longer be visible to them.  The only folks that will be able to view that field going forward (in Edit and Display Mode), is the Managers. 

Disable field if: not(New Form)

Hide field if: and(not(New Form),not(IsMemberOfGroup("Managers")))

NB: if the IsMemberOfGroup inline function is not listed, just type it as fn-IsMemberOfGroup

Thanks for the reply! 

Those formulas don't seem to work for me.  Do I also need to use "fn-and" ad "fn-not"?  I couldn't get those to work either...

That's odd, as the listed inline functions should work without any issues. Are any of the inline functions working. Just to be sure: use a calculated field on the form to show results for logic operation, e.g. and(true,true) -> true, and(true, false) -> false.

Are you using the correct separators , or ; in the functions?

Is it a classical form or a responsive form?

I got it!  I missed your call out on adding the "fn-" before Is Member.

Thank you for your help!