If you would like to have accurate tracking, the recommendation is to have local landing pages.
If you would like to have global landing pages where you can change something on that landing and have it reflect on all of your landing pages, you'll want to build an entire langing page template. Then, you'll want to use that landing page template to create your landing pages (without changing or creating anything on the landing page)
However, please note that if you make a change to a landing page template, you will still need to go and approve each landing page that is using that template in order for those changes to take effect.
In short, you won't be able to create global landing pages - you may only clone them. You can create global landing page templates
Hope that helps.