Ride Sharing Services like Uber, Lyft and many more are increasingly common and in many cities can be a good option for airport transfer. They are well entrenched albeit in some cities they are still struggling to get official government sanctioned legislation in place to support them.
You need to sign up online to be a part of these services. Of course one sign up globally is enough. The service will bill your account in the local currency which your credit card company will transfer to your home currency (where your account is held) at the local exchange rate. International transaction fees will likely be added.
At the large airports, there is a designated area for ride sharing pick ups. These are well sign posted in the airport. The designated area are usually curb-side but maybe in the middle median strip or perhaps with hotel shuttle pick ups accessed under the street and back up. Follow the signs
The driver may not speak English in a non English speaking country. However, the driver’s app will map out the most direct route to your destination.
In some cities Uber dominates (eg Dubai) but in others it may not be the prevalent ride sharing app. In Shanghai, for example, there are more than one well established Chinese equivalent. You will need to change your settings on your app if you are using Uber in a non-English speaking city. Otherwise, the maps and addresses will come up in the local language. Uber is so prevalent in some cities that major hotels have a designated lane out the front for Uber pick-ups. This is to avoid congestion in the driveway (eg Ritz Carlton in Shanghai) with taxis and other vehicles arriving and departing.
In cities which have Uber Pool (or equivalent), remember that you may be refused by the driver if you are travelling to and from the airport with too much luggage. This is because you may fill the trunk/boot with suitcases and leave no room for the next rider. Once suitcase and a carry on are usually accepted – it is up to the discretion of the driver.