Google posts Android 6.0 Marshmallow factory images
Last night, Google posted the Android 6.0 Marshmallow factory images online, for the Nexus 5, 6, 7 (2013), 9 (Wi-Fi), and Player. since these are factory images, you'll have to perform a wipe and install. If you don't want to go through the hassle of doing so, you'll have to wait for the OTA updates rolling out in the coming weeks.If you want to take the plunge, AndroidCentral has a great guide on how to do so.