I am not with Laminar Research; just a flight simmer.
The official version of X-Plane from Laminar Research, particularly the digital download, can be installed on any number of computers. However you can only legally run one copy at any one time. You need to be connected to the internet at all times as there is a background check performed to check on how many versions are running at that time using the same installation key. A steam version is not the same version as the Laminar Research version.
In relation to your surface Pro 6 windows based laptop check the specifications which can be found here at https://www.x-plane.com/kb/x-plane-11-system-requirements/ Serious x-plane users build a purpose built windows based unit equal to or better than the recommended specifications.
What is not mentioned is you need a dedicated graphics card with a screen at least 17 inch in size just to get a reasonable screen image. Anything smaller will be difficult to read. An integrated graphics port with the motherboard will not operate satisfactorily or at all. What is not also mentioned is your unit requires good internal cooling as the processor and graphics card generates heat that needs to be exhausted. If no additional cooling then it will overheat and your system will crash.
I am also of the opinion your system is well below minimum system requirements and will not run.