Every worker of Space Station 13 is issued an identification card. Your ID has your name, occupation, and a device that broadcasts your access to the station's autonomous systems, which is used both to identify the holder and open up airlocks the worker has access to. For example, the Quartermaster has access to the Cargo Bay and Quartermaster's Office, while Assistants, for example, do not. ID cards can have their access modified by the Captain or Head of Personnel. When your face is covered your ID is the only way of identifying you. Alt clicking an ID card allows you to withdraw credits, or if no account is set allows you to link an account (number found in IC tab under memories.) Smacking an ID card or a PDA with an ID inside with money, holochip or cash, will deposit credits into the account. Money is also occasionally added depending on job and species and the HoP's office has a terminal which can view certain purchases made with ID cards.
Types of ID cards
Standard ID - The basic card. This only has two wildcard slots and can carry only common accesses.
Silver ID - The Heads of Staff card of choice. This has five wildcard slots for extra accesses that can carry up to 3 common, 1 command and one private command access.
Captain's ID - The card of choice for all access. This has unlimited wildcard slots at the Captain level, capable of taking all station accesses.
Centcom ID - Identification card issued only to Centcom officials, including Death squad officers. The card of Central Command. This has unlimited wildcard slots at the Centcom level, capable of taking all station and Centcom accesses.
Syndicate ID - A black card of syndicate origin. This has unlimited wildcard slots at the Syndicate level, capable of taking all station and Syndicate accesses.
Prisoner ID - Identification card issued to prisoners, so they can be identified on the crew monitoring console and keep track of labor points. No wildcard slots at all.
Holopay
Ready to start a business?
You can summon holographic pay stands by right clicking an ID. They have a limited range that projects from the card itself. Clicking the holopay opens a terminal that can be customized by the holder of the card. These settings persist on the card itself, no need to reset every time.
Force Fee - By default, users can pay what they want via terminal. However, you can manually set what users must pay. This will be indicated in the UI and they will be asked to confirm payment in this case.
Trims 
Can be edited with a PDA & ID Painter machine. The trim determines which basic access slots a card have. A card can be granted all its current trim's basic slots without consuming wildcard slots.
Grey ID cards cannot hold Head of Staff or Captain trims. Silver ID cards can hold Head of Staff trims but not Captain trims. Gold ID cards can hold all access.
Wildcard Slots
These are any additional accesses a card can get that are not part of the card's trim. Lower rarity ID cards have fewer wildcards and the wildcards they do have are of lower rarity (common vs command).