Add or create trips in Google Trips
Your trip reservations are automatically gathered from Gmail and organized into individual trips. If you have reservations-related emails in a different account, forward them to your Gmail account to automatically create a new trip.
To manually create a trip:
From the “Your trips” home screen, tap Where do you want to go? and enter the destination (or the first destination, for multi-destination itineraries) in the search box.
Once you’ve entered a place, you’ll see the home screen for that destination.
Tap Create trip to add the destination as a new trip. Make sure to select the dates and any additional destinations.
Tap Done to save to Your trips.