Paris Museum Pass
This pass is highly recommended as it often allows you to skip long museum lines and actually can save you some money. You can buy a 2, 4, or 6 day pass. This gives you access to something like 60+ museums and pretty much any you will want to see. generally you’ll skip most lines (not security) and get in much faster. There may be a few places (like the Louvre) where in addition you may need to get a timed entry but in general, don’t visit Paris without this pass. It is available at tourist offices, certain kiosks and stores, the airports, and online
Paris Pass
DO NOT mistake the Museum pass for the Paris Pass which is generally not a good deal – the Paris Pass includes transportation, museums and other attractions but we’d skip most of the other attractions (that drive up the price). You can get a Visite Pass for transport and the Museum pass and save a lot of money
Visite Pass
This is a multiway metro / transit pass and makes getting around Paris on the Metro a snap. You can buy individual metro tickets but this is much easier. For almost all of Paris you need a zone 1-3 pass. For Versailles and the airport a zone 1-5. It might make sense to get the 1-3 zone and just buy individual tickets to the outer areas if you don’t need them each day