The macOS offers direct support for Exchange servers from version 10.6 (Snow Leopard) with the standard mail software:

https://support.apple.com/de-de/HT201729

When setting up the mailbox, please select the server type "Exchange" and then enter your name, email address and password. If you are then prompted for a user/login name, please enter your known username that you also use to log in to UWE, Wlan, Intranet, etc.

If you are asked for internal and external server addresses, please use the following settings:

Internal server: owa.uni-wh.de/EWS/Exchange.asmx

External server: owa.uni-wh.de/EWS/Exchange.asm

For configuration of iOS devices (iPhone, iPad) please read on here. Thank you!