How to create a shortcut to an email account on Galaxy S7 Edge?

You can place a 4 x 2 scrollable Email widget that link to a particular account on your Home screen. The pre-installed Email app doesn’t offer a 1 x 1 account widget.

If the 1 x 1 account widget is what really important to you, try one of the following 3rd party Email apps:
1. Blue Mail.
2. WPS Mail.
3. K-9 Mail.

Alternatively, you can setup your email accounts in the Gmail app (Yes, now Gmail supports 3rd party account), and then place the 1 x 1 label widgets to have them link to different accounts on your Home screen.