The passport contains the identifying information of the player and Uncle. It is used to grant access past border checkpoints during the player's journey. This makes the passport the second most important tool in the game. Without it, you cannot progress.
While at a checkpoint, the officer will instruct the player to show them their information. To do so, the player must roll down the window, if it isn't already, and use the passport on the officer. At this point, another officer may check the trunk of your Laika for banned goods. If all goods are allowed into the country, this inspection will not occur.
The passport is always located inside of the glove compartment in the Vehicle. Should the player ever drop their passport by pressing Q, it will automatically return to the glove compartment instead of falling to the floor.