PTIN: Most individuals paid to prepare, or assist in preparing, all or substantially all of a federal tax return must obtain and renew an IRS Preparer Tax Identification Number. A PTIN is not an IRS license or proof of expertise.

EFIN: An Electronic Filing Identification Number identifies an authorized IRS e-file provider. It is distinct from a PTIN; an EFIN is not a professional credential.

Enrolled Agent (EA): A federally authorized tax practitioner with unlimited practice rights before the IRS, subject to applicable rules. Not every paid tax preparer may represent clients in all IRS matters. Never claim credentials or representation rights you do not hold.