Call the IRS at 1-800-829-1040 for individual tax questions
Call 1-800-829-4933 for business tax questions
Visit the IRS website at IRS.gov
Use the IRS online tools and account services at IRS.gov
Mail correspondence to the address listed on your IRS notice or form instructions
Visit a local IRS Taxpayer Assistance Center by appointment
Call the Taxpayer Advocate Service at 1-877-777-4778 for help with unresolved problems
Use the IRS contact information printed on your tax notice or letter