IRS guidance for this is here: https://www.irs.gov/newsroom/deferral-of-employment-tax-deposits-and-payments-through-december-31-20...

Did you mean the info on the W2 for the Employee; or, are you working on the business return for the Employer? Or, for a self-employed person?

There is nothing reported on the W2, however the client provide an email from HR state that the SS tax  was deferred and will be recovered in 2021.

"There is nothing reported on the W2"

That's not how the regulation reads.

"However, do not include in box 4 (Social security tax withheld) any amount of deferred employee Social Security tax that has not been withheld."

From: https://www.irs.gov/forms-pubs/form-w-2-reporting-of-employee-social-security-tax-deferred-under-not...