To activate TurboTax after installation, launch the TurboTax software on your computer. When prompted, enter the 16-character license code found on your product box, email receipt, or online order confirmation. Follow the on-screen instructions to complete the activation process. Make sure your internet connection is active during activation. If you encounter issues, double-check your license code and try again. For additional help, visit installturbotax.com for detailed support and troubleshooting tips. Activating your TurboTax ensures access to the latest updates and allows you to begin filing your taxes with confidence and full functionality.