Studio lighting is what separates many professional portrait photographers from the amateurs. That's not to say that you can't achieve wonderful shots with natural light only – of course this is possible. But for formal or glamorous portraits, flexibility is capable of controlling light in total it will produce a few strong shots.
The basic studio lighting kit, is quite flexible for various shots, consisting of two lights, with umbrellas and / or softboxes. If you are shooting people it is preferable to use studio strobes, which act as a jumbo sized version of your normal on-camera flash.
The alternative to this is continuous lighting – think floodlights – which can still be effective, but produce less power overall and have heat and energy usage problems.
This setting can be used in many configurations – general settings are using one light on one side of the subject and other lights on the opposite side on half the power of the first light. This setting will provide opportunities with some shadows to emphasize features, but the shadow won't be very dark – good if you try to show the full face or subject body.
Another option is to use only one light on one side of the subject, and the second light to become background lights or hair lights. Background lights are useful for making the subject stand out from the background, but must have a much lower power than the main light in many cases.