Passing Query String Parameter to Rest API

Hi All

 I have a requirement where I 

1. Need to get data from Rest API and this API need one parameter and that is Userid. 
2. Report needs to be embedded in .Net Application through App Own & SPN approach 
3. Userid needs to pass from .Net Application so loggedin User will be able to see their data only. (Requirement & due to Performance)

Question

1. Can we pass UseriD in Rest API Query that is passed as Query String Parameter from application.
2. I know Parameter can be set by application by REST API but if 2 user will login and will access the report from .Net application  then will both user will get their respective data in embedded application only as we have only one report published in power bi service ?