Click here for same as previous field

I have a field for PayPal email address in addition to an email address field.
A lot of times this field will be the same as the user’s email address.
So I wonder if there’s someway to have a checkbox to user the useremail (another form field) as Paypal email?

This is similar to website forms where there’s a checkbox to use shipping address as billing address and it auto fills when you click a check box.

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