Some phones have a toggle arrangement on the side of the phone. There are other models that require you to go into the menu settings. Refer to your owner's manual for your particular model. You may also be able to ask your providers customer care representative. In most cases, you will have to go to the phone's menu program to make this adjustment.
Many models also allow the ringer to be completely turned off.
This is a great feature for meetings or any other time you do not want to be disturbed by the ringer, but want to leave your phone on. You can call anywhere unless you put international restrictions on your plan. You may have to be in your local calling area to initiate the call depending on the plan you have. Your first cellular bill is usually larger than your average monthly bill. Many carriers charge an activation fee to set up each line.