How can I remove the Outlook app from my Honor Holly

If it's a system app you can't, otherwise Go to Settings > Security > Device administrators > and uncheck the app.Uninstall as you normally would.
 
On a US model Honor 8, to remove an app from device follow these instructions: Open Settings > Scroll to Apps and select it > Select the app you are looking to remove > Select Uninstall.

If the app you are trying to uninstall is a system app the device will give you the option to disable it in place of the uninstall option. Hope this helps! (SV)