If you are not aware of the key combination of your device to boot it into recovery, use an app like Quick Boot from the Google Play Store to avoid all the hassle. The process usually involves switching off your Android device and then pressing a specific key combination.
Step 2: Reboot your device into the custom recovery like TWRP installed on your device. Step 1: Download Xposed framework for Marshmallow and the accompanying APK from below, and then transfer both files to the internal storage of your Android device. P.S.: The version of Xposed framework for Marshmallow linked below does not work with Samsung devices.
Note: As always, it is recommended that you create a backup of all your important data before proceeding with the steps below. Like with previous versions of Android, installing Xposed framework under Marshmallow remains largely the same and so do the pre-requisites: a rooted Android device running Marshmallow with a custom recovery like TWRP installed. Just over a week ago, rovo89 released the first alpha of Xposed framework for Android 6.0 Marshmallow. Since Marshmallow did not come with radical underlying changes like Lollipop, it took the developer relatively less time to port the framework to Android 6.0.