Answer:
Employers filing 10 or more information returns, including Forms W-2, must file electronically unless granted a waiver by the IRS. All employers are encouraged to file Forms W-2 electronically.
The information returns that count toward the 10-return threshold are:
- Form 1099 series
 - Form 1098 series
 - Form 1097-BTC
 - Form 3921
 - Form 3922
 - Form 5498 series
 - Form 8027
 - Form 8851
 - Form W-2
 - Form W-2G
 - Form 8955-SSA
 - Form 1094-B
 - Form 1095-B
 - Form 1094-C
 - Form 1095-C
 - Form 1042-S (For purposes of Forms 1042-S, a financial institution must file all returns electronically regardless of the number of forms being filed.)
 - Form 8966 (An entity that is a financial institution is required to file this form electronically, irrespective of the number of Forms 8966 filed.)
 
Forms W-2, whether filed on paper or electronically, are filed with the Social Security Administration (SSA). For specifications for filing Forms W-2 with the SSA, visit SSA.gov/employer or call 800-772-6270 (TTY 800-325-0778)