How to get to the city center
It depends on the airport but the most common to arrive is Domodedovo which is really far. It´s about 47km. You have several options to get to the city center:
1. Taxi: is the most expensive and also the comfy way. You are going to find a lot of taxis cab outside the airport and those ones are the most expensive. There is an app like Uber there which have a stand inside the airport. You can talk to them and they are going to give you the price. This app is the cheaper way if you want to take a taxi. It´s about one hour to the center but it depends on the traffic and the time.
2. Bus: Out of the airport are several buses which takes you to the center and they are really cheap. The bad side is they are like 8 minutes walking out the airport and if you have luggage it won’t be comfortable. About the time is more than an hour this also depends on the traffic.
3. Train: for me the best option. The airport has an own train station which you can take on the second floor. It’s a cheap and fast option. It will leave you in a metro station in the center so you can take a taxi to your hotel or keep connecting on the metro.
If you buy the tickets online they are going to be cheaper, If not you can buy it at the airport. Here is the web page so you can check it out.