Download Systemless Xposed Framework for Oreo
Systemless Xposed Framework is made by Topjohnwu the master of Magisk Su. He also ported the Official Xposed for Oreo to the Magisk. But the Thing is it cannot pass the Safetynet Measure by google as of now. Maybe this may fix in further updates by Topjohnwu but not guaranteed.
SDK26 = Android 8.0 and SDK27 = Android 8.1+
Download Xposed Installer Apk
Xposed Installer is used for the managing the modules of xposed framework. You can see the xposed status is active or not. This is the modified version of Xposed Installer by Topjohnwu that will detect Systemless Xposed Properly.