Boosting service is a pumping service. This is the most common concept that includes all possible types of services to improve the account, the development of the game and the character, as well as everything that has something to do with the game, including the likes of screenshots from the game on social networks. Anything you wish as they say.
The type of service can vary greatly depending on the type of a game. For example, in online shooters like CS:GO or PlayerUnknown's Battlegrounds, you can order a pumping of rating, a certain number of wins in battles or hours spent in a game. Conditions may also differ. When ordering an urgent account boosting, few professional players working on the schedule can start their work, and then the character will move from one battle to another almost in 24/7 mode. Of course, such services will not be expensive. Another option is a "season ticket" for gradual boosting, at that, a professional player will play for you several hours a day for a month or even more than a month. Of course, in the first and in the second case a good result is guaranteed in 60-70% of victories.
For quest games like World of Warcraft, the range of services for boosting is even wider. Here, you can order everything at professional experienced players, from the help in the game from another character to performing daily tasks and promoting the character and the game itself to the desired level. In this case, it is not always necessary to give your account into the hands of a professional, the customer can play the character on his/her own and only accept help or pump skills at the expense of a professional player character, along with valuable advice from him/her.
The range of offered services is almost infinite, it is negotiated separately with each customer. But there are rules that are valid for all boosting services. The first is the transfer of the account into the hands of a professional, if it is required, it is strictly confidential, the security of the account is guaranteed. And the second one, any boost of the rating, character, progress, etc. It is carried out exclusively due to the experience of professional players, without the use of bots and cheats.