A VPS stands for Virtual Private Server. As the name implies it is your own private server which is hosted in the cloud/on the Internet. Like any server it is always on 24/7 and constantly online.
Think of your VPS as a personal computer that you rent on a monthly basis. This computer is located within our datacentre based in the UK. You then access your computer through the internet and install your MT4 terminals so they run 24hrs per day.