Right now Apple Pencil doesn’t come with its own dedicated charger. You need to lift off the rear and then use the male Lightning connector that you need to insert into your iPad Pro. According to the official Apple website:
Slip off the magnetic cap of Apple Pencil to reveal a Lightning connector that lets you charge Apple Pencil simply by plugging it into iPad Pro. The connector features a slightly elongated design, so that charging is possible even when iPad Pro is inside its Silicone Case. In a rush? Just 15 seconds provides enough charge for half an hour of use. And a full charge gets you 12 hour’s worth of scribbling, sketching, annotating, and editing.
Your iPad pro is being charged right now and so its port is already occupied? No worries if you also have an iPhone or an iPod. You can insert the Lightning connector into your iPhone or iPod and charge your Apple Pencil. As the above quoted description says, even 15 seconds of charging can give you half an hour of usage.
According to this 9To5Mac post, Apple is soon going to ship a dedicated Apple Pencil charging adapter that will allow you to charge your pencil without having to plug it into your iPad, iPhone or iPod. Once the USB Lightning cable is available, you will be able to charge your Apple Pencil from a wall adapter, from computer’s USB port or any other power source that you are already using to charge your iPhone, iPad or iPod.