Taxpayer First Act of 2018 This bill modifies several administrative procedures and policies of the Internal Revenue Service (IRS). The bill includes provisions regarding programs that assist taxpayers in filing returns; relief from joint and several liability for a joint tax return; whistle-blower protections; the retention of electronic records; rehiring, removing, or transferring IRS employees; limitations on the access of non-IRS employees to tax returns and return information; the filing requirements for tax-exempt organizations; IRS audit criteria; protections against identity theft and tax refund fraud; penalties for the improper disclosure or use of information by preparers of tax returns; transferring appropriations between IRS accounts to combat tax fraud; streamlined critical pay authority for certain IRS information technology positions; an Internet platform for Form 1099 filings; and the electronic filing of tax returns.