To sign the back of your card, simply take a good black ink pen and sign your name including your first, middle and last name cursive and that will be your authorized signature.
You can use a card if it's not signed, as not having a signature on the card does not prevent the card from working, however if not signed the card may not be accepted in person if they swipe it themselves such as in a restaurant.
While you don't have to sign the card, some merchants may refuse to accept it for payment and some merchants might require a signature when using the credit card or debit card as well on their keypad.
For most credit card transactions, signatures are not required as the Major credit card networks such as Mastercard, Visa and American Express and even Discover card have dropped their mandates for signatures and instead rely on chip technology or EMV and PINs for security.
However many establishments, like restaurants maintain their own signature process to allow their customers to add a tip to their bill.
And individual businesses and post offices such as the USPS can still legally require you provide a signature or matching ID as part of their own corporate policy or for loss prevention.
And if a store chip reader happens to malfunction, the older credit card terminals might even default to swiping the magnetic stripe and require a signature when you use your credit card.
Some cards ask for a signature mainly for security as well to acknowledge agreements and even for leaving a tip.
Although major card networks such as Mastercard and Visa have mostly phased out requirements for signatures, the individual merchants sometimes still require your signature to process the card transactions.
The specific reasons for the signature of the cards include.
For the back of the card, the card issuer like the credit card or debit require you to sign the back of the card to validate the card and establish a signature for merchants to compare against.
The signature you sign on the back of your card, acts as a baseline fraud deterrent, even if it is rarely checked.
For tipping with your debit or credit card, service businesses and restaurants usually default to their own 2 step payment method of swiping the card first and then bringing you a receipt later, so you can easily add a gratuity.
And some merchants still use older magnetic stripe registers or even if they have a broken chip reader it may force the system to print a physical receipt to sign when you use your credit card or debit card.
And in some cases, a signature formally authorizes a contract or acknowledges the receipt of goods.
As for the signature requirement on the back of the credit card or debit card, not signing the card will not prevent the credit card or debit card from working.
The cards chip, magnetic stripe and the contactless antenna inside the card all function on their own independently of the signature strip.
However if the credit card or debit card is not signed, retailers and merchants have their own legal right to decline a transaction if they notice the card is unsigned.
And if a clerk or merchant spots the blank panel for the signature, they are also technically required to ask you for a government issued photo ID and make you sign the card on the spot.
And if your unsigned credit card or debit card is stolen or lost, it is also much easier for a thief to sign your name in their own handwriting and use it, which can complicate your fraud protections with the bank.