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 can still occur. If you attempt to bring banned goods over the border and the officer checks your trunk, they will be confiscated and you will be fined.
The passport is always located inside 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.