To contact QuickBooks Desktop Support by phone, you can call their customer service number at 1-855-200-0590. This number will connect you directly with a representative who can assist with various QuickBooks Desktop issues, including software installation, troubleshooting errors, and managing your account. Support is available to help you resolve any technical difficulties you may encounter with QuickBooks Desktop, ensuring your accounting processes run smoothly. Be sure to have your account details and any relevant information handy when you call to expedite the support process.