Hit the ATM
You'll likely be able to use your Visa credit card at an ATM to acquire cash. Much like with a debit card, you'll need to enter a personal identification number. If you don't have one or forget what it is, contact your credit card issuer to get a new one. If you're given a choice as to where to get the money from, you'll usually have to select the "credit card" option. The ATM will alert you to any fees that its bank will assess for the withdrawal, but won't detail what you'll to pay the Visa card issuer.
If you received convenience checks from your card issuer, you can use these to secure a cash advance as well. Deposit them into your checking or savings account as you would a personal check. One risk with this approach is if the check exceeds the amount of your credit line that's available for cash advances. That would cause your check to be returned by your Visa card issuer, which likely would mean both the card issuer and your bank would charge you a fee related to the returned check.
At the Bank
Visa cards issued by a bank can typically be used to get cash advances at any branch. You'll have to go to a teller and show identification to complete the transaction. You also may be able to transfer cash directly from your credit card to your bank account. This could occur if your accounts are linked, like if the Visa card is issued by the financial institution where you do your banking. This transaction could take place at the branch, over the phone, at an ATM or online, depending on the policy of your card's issuer.
Visa card issuers penalize you for taking a cash advance. You'll pay a transaction fee based on the amount of the advance, and you will likely pay a much higher annual percentage rate on that amount than you will on purchases. Often, there's no grace period associated with cash advances, meaning you'll start accruing interest on the amount borrowed as soon as the transaction takes place. Should you find yourself needing a cash advance, pay off that balance as soon as possible to minimize the extra costs.