To contact the U.S. Accounting Tax Helpline online, you can visit the official IRS website at Accounting Tax helpline number. On the site, you’ll find various resources, including contact details for different tax-related inquiries. For direct assistance, "Contact Us" section for specific guidance. Additionally, the company provides phone numbers for various departments, including a general customer service number at +1.833.677.8666 for tax-related questions.