She can drive a motorcycle.
This means that she is able to drive a motorcycle, or that she has permission to do so.
She drives a motorcycle.
Usage of present simple in this way indicates a habitual action, like "she smokes". Depending on the context, it could mean that she prefers to get about on a motorbike, rather than a car, or (if the listener had asked what she did for a living) that she is a motorcycle courier.
Note that most English speakers would use the verb ride for a motorcycle, rather than drive. Also note that you need an indefinite article a before motorcycle, because it is the singular of a countable noun.