If you want a function or field available for admin use, but not available to the general public, here is how you can set that up.
Add a text field to your page and label it 'Admin Use Only' - make sure it's not required.
Set up the function or field you want to hide.
In this example, I'm going to set up offline payments. But you can apply this to other functions as well.
Set up a SHOW action that requires a specific value in the text field.
You can set that value to be anything you want. For this example, my password is 'officeadmin'.
Note: Actions automatically assume the opposite is true. Meaning, it will know to hide it unless that specific value is entered.
Save and preview to test.
Now only admins with the correct "password" will be able to use that feature on the live page.
FAQs
Is the password case-sensitive?
No. But it is space-sensitive. If you set up the password to be one word, typing it as two wouldn't work.
How will this pull into my exports?
The fields hidden will be populated with data when used, and empty when not used.