Yes, there is a setting on the phone you need to change, but I can't recall off the top of my head exactly what it is.
If you have the phone turned on when you plug it in as a USB device you should get a pop-up on the screen asking you whether you want to allow a connection to the PC which you can answer and, I believe, there is a checkbox regarding remembering the answer.
Also have a look at:
https://www.technipages.com/galaxy-s7-how-to-connect-to-pc (this one mentions the prompt I recall getting)
https://community.verizonwireless.com/thread/909255 (which is a Verizon specific Q&A that makes reference to the same setting discussed in thecellguide)
What you're experiencing is not limited to the Galaxy S7 but to newer versions of Android. Once I tweaked the setting to allow the device to act as a media file transfer device (which also allows it to charge) it gets treated as an external drive where the phone's internal memory is one logical drive and the micro SD card another.
Brian AKA Bri the Tech Guy (website in my user profile) - Windows 10 Home, 64-Bit, Version 1803, Build 17134
. . . the presumption of innocence, while essential in the legal realm, does not mean the elimination of common sense outside it. The willing suspension of disbelief has its limits, or should.
~ Ruth Marcus, November 10, 2017, in Washington Post article, Bannon is right: It’s no coincidence The Post broke the Moore story