I saw this in a course for customer-service representatives.

Problem:
The list of adverbs contains redundancies.

Explanation:
The expression was part of legal counsel in a company’s course for its customer-service representatives:

“Permission [from the customer] can be obtained verbally, in writing, or electronically.”

Unfortunately, it has become a common English blunder to use the adverb “verbally” when people mean “orally” instead.

The adjective “verbal” refers to both oral communication and written communication.

But many people shy away from “oral” or “orally” when referring to spoken communication and instead use “verbal” or “verbally”, respectively. This is a mistake.

The second problem in the expression is that “in writing” refers to both paper-based communication and electronic communication.

So “in writing” overlaps “electronically” in the problematic expression.

The solution comes from recognizing that “verbally” should be replaced with the clearer adverb “orally” and that “in writing” should be replaced with the clearer “on paper”.

Solution:
“… obtained orally, on paper, or electronically.”
OR
“… obtained by telephone, by mail, or by email.”