Can i upload same files to Adobe Stock and some other site Shutterstock and Freepick etc

Of course you can submitt same assets to competing microstock services.  But it diminishes the value of your work.

If customers can get the same asset cheaper from another stock service, they won't buy from Adobe Stock. 

Stock typically pays higher royalty fees than competing services.  So it's in your best interest to submit other assets to competitors, perhaps the ones that Stock rejected.  😉

We can't ascertain what relationship you have with other stock agencies; however anything uploaded to Adobe is non-exclusive, which means that you can sell it elsewhere. Read your Stock Contributor Agreement.