The most common way is to have team members place calls on behalf of a queue, and set the Calling Party Name and Calling Party Number in the Voice settings on the queue.
So, first you would have to have PureCloud Engage licensed, set up a queue under Admin>Contact Center and add your team as Members, and make sure they all have the Engage User role assigned.
Then, modify the settings on the Voice tab of the queue configuration:
To place a call, the user clicks the Interactions icon in the left sidebar:
Then types in the name of the queue to call on behalf of (it will pop up with names as soon as you start typing) and the number to call (or open the dialpad):
And click the green phone to place the call.
There are some other, more complicated settings that can be used under Telephony on the Trunk configuration, but that is less flexible and requires use of Perl Regular Expressions to translate the user's assigned calling party number into something else.