To disable the tweet location, follow these (almost identical) steps:

1. Log in to your Twitter account.
2. Click on your user photo from the top right corner of the screen.
3. Go to Settings from the drop down menu.
4. Click on Security and Privacy from the left menu.
5. Go to Tweet location and disable the “Add a location to my Tweets” option.
6. From here you can also delete the previously stored Tweets location information.