If you have a bank account it is possible to obtain credit by drawing out more than is in your account.
However, overdrafts should always be approved with the lender as fees for unauthorised overdrafts are hefty. Some banks offer a free overdraft facility up to a stated figure.
Interest will still be charged, but only on the amount drawn out. Whereas overdraft fees can often be charged on each purchase made that goes over the agreed limit for the account. This will be in addition to interest charges.