How to go from all four Moscow's (DME-SVO-VKO-ZIA) international airports to the city center? [closed]

As Neusser has already answered (+1), the simplest way it to take Aeroexpress speed train that connects each of the three main airports (Sheremetyevo, Domodedovo and Vnukovo) with stations in Moscow center. It is rather expensive, especially if you travel in a group (and hence need several tickets), but runs on time and without any problems. Just check the timetable in advance, as the intervals between successive trains are relatively long (from 30 minutes to 1 hour, and a long break in night).

Another option is taxi (better order a taxi through app such as Yandex.Taxi or Uber; some airports AFAIK even have kiosks to order Yandex.Taxi). This is more expensive that Aeroexpress if you travel alone, but can even be cheaper if you travel in a group. However, travel times are often unpredictable due to Moscow traffic.

There are also regular buses that connect the airport with subway stations. They are very cheap, but they can be slow (due to traffic and/or due to their schedule), and you may find the whole system harder to understand (you should find the needed bus numbers in advance, find where they stop at the airport, check the schedule etc.) Also they will bring you only to a subway station on the outskirts of the city, and you will need to take additional subway ride.

Note also that Zhukovsky is a very small airport only recently put into operation, so there is no Aeroexpress, and other transportation options may be limited.

I think that a decent option is Uber or Yandex.Taxi app. The caveat here is that you would want to already have local SIM with data plan. If you come with international SIM you can spend on data in the roaming more than on the cab. Most likely, you can pick up a data SIM in the airport.