I check Google Play Store (that’s the name of Android’s store, not App Store), but I could only find Unity Remote and Unity Remote 5. I have a Samsung Galaxy S7 with Android version 6.0.1 and it doesn’t have an “Allow mock locations” setting; it does have a “Mock location app” setting with 3 options: No apps, Contacts, and Messages. I’ve followed all the other instructions
I didn’t find Unity Remote 4 either, but I got it working with Unity Remote 5. There is another topic to this lecture which tells you how to do it: https://community.gamedev.tv/t/unity-remote-5/9087