I'm not with Laminar Research, just a fellow simmer in the UK.
Assuming that you are using a valid copy of X-Plane 11 purchased from LR i.e. a digital download, then you can do one of two things:-
1. Copy and paste the entire X-Plane 11 file structure from one PC to the other
2. Re-download X-Plane 11 again from the LR website
Either way, you may need to enter your original product key again, depending on which option you use.
If you are using a valid DVD set from LR, then just re-install as previously, if required.
If you are using a copy of X-Plane 11 from any third source i.e. Steam, then please refer to them before doing anything.
Hope this helps