In order to e-file tax returns on behalf of a client, you must have an Electronic Filing Identification Number (EFIN) assigned to you by the IRS. To apply for an EFIN, go to
irs.gov and complete the e-file application.
If you need help completing your e-file application, call the IRS e-help desk at 1-866-255-0654. It can take up to 45 days for the IRS to process your application and issue you an EFIN.