Artboards can be created with new documents or added to your current document at a preset or custom size at any time.
When creating a new document, you can automatically create your first artboard using the settings in the New Document dialog.
Once you have a document open, you can add additional artboards in different ways:
Artboards can be deleted from your project at any time. Any objects placed on the artboard can either be kept or deleted (you're prompted to confirm which action you want to take via dialog). Kept objects will remain in their original position but will be on the pasteboard instead.