Before we get to the details, here is some general information:
Please be aware that game progress does not work the same way for host and client in a co-op session. This article will give you all the details.
You will need an internet connection as well as an active console membership (Xbox Live Gold or PS Plus) to play in co-op mode.
Additionally, please make sure that co-op mode is enabled in your game's settings.
To set up a co-op session, you can invite one of your friends to join you. The invitation is based on the friends list of the platform you are playing the game on (PS4, Xbox One, PC). Co-op mode is not available cross-platform. The friend you'd like to play with needs to be on your platform's friends list. Simply invite a friend from your list from the game's Main Menu. They will receive an invitation and once they accept, they will automatically join your game and appear near your character with the character they customised during their own single player campaign.
Players can interact with each other in a co-op session, for example by exchanging ammunition or medkits. Also, friendly fire is possible. If you wish, you can turn on the friendly fire option in the game's settings - It is disabled by default. However, players in a co-op session cannot travel too far from each other. Once a certain distance threshold is reached, the guest will automatically be teleported back to the host player.
If you'd like to know more about playing co-op in Far Cry 5, feel free to take a look at this comprehensive post on the official Far Cry 5 website.
Should you encounter any connection issues while playing co-op with your friend, you might find the information we put together in our connectivity FAQs for PC, PS4 and Xbox One interesting.
Please feel free to get in touch if you have any questions.