North Greenwich is a London Underground station served by the Jubilee line. It is located on the boundary between Travelcard Zone 2 and Travelcard Zone 3. According to the London Wiki, North Greenwich station is on the boundary of zone 2 and 3, so if you are coming from London, it is in zone 2, so a zones 1-2 travelcard will suffice. The station is actually closer to Charlton than to Greenwich, but it is at the northernmost tip of the Royal Borough of Greenwich, which perhaps gives the best explanation of the name.