TSA PreCheck to your United Airlines profile, start by logging in to your account on the United Airlines website or mobile app. Navigate to the Account section, then select “Profile” or Travel Documents. How Do You Add TSA PreCheck to United Airlines  Look for a field labeled “Known Traveler Number” or similar, and enter your TSA PreCheck number there. Save the changes to update your profile. Once your TSA PreCheck number is added, it will automatically be applied to future bookings, ensuring your boarding passes include the TSA PreCheck indicator. This will help you enjoy expedited security screening at participating airports.