Although the details are scarce, it appears that Honor 6X owners will simply need to email their IMEI to the following address, "huaweifut@huawei.com", and wait for a response.
Android 7.0 Nougat will bring about many new features to the handset like the multi-window split screen and advanced Doze feature that will increase battery life. But perhaps the biggest difference with Android 7.0 for the Honor 6X will be the update to EMUI version 5.0, that will offer an app launcher by default. As mentioned previously, Honor has not offered any further details, but if you"d like to participate in the beta, you can email your IMEI to the email address above or head to the source link below.
Source: Honor USA (Twitter)