From the ARRL Letter, January 7, 2021:
Effective on June 29, 2021, amateur radio licensees and candidates must provide the FCC with an email address on all applications. If no email address is included, the FCC may dismiss the application as “defective.” The FCC has already begun strongly encouraging applicants to provide an email address and will email a link to an official electronic copy of the license once it’s granted.

While many, if not most, amateurs already have provided an email to the FCC, this also will become a requirement. Under Section 97.21 of the new rules, as amended, the holder of a valid amateur radio station license “must apply to the FCC for a modification of the license grant as necessary to show the correct mailing and email address, licensee name, club name, license trustee name, or license custodian name.” For a club or military recreation station license, the application must be presented in document form to a club station call sign administrator who must submit the information to the FCC in an electronic batch file.

Under new Section 97.23, as amended, each license must show the grantee’s correct name, mailing address, and email address. “The email address must be an address where the grantee can receive electronic correspondence,” the revised rule will state. “Revocation of the station license or suspension of the operator license may result when correspondence from the FCC is returned as undeliverable because the grantee failed to provide the correct email address.”

Licensees can log into the ULS License Manager System with their FRN and password to update their FCC license record, including adding an email address. For questions or password issues, call the CORES/FRN Help Line, (877) 480-3201 (Monday – Friday, 1300 – 2300 UTC) or reset the password on the FCC website.