
WhatsApp worked on Companion Mode earlier this year to connect a second mobile device, and the company is now rolling out companion mode on Android to some beta testers. WhatsApp launched communities, in-chat polls, and 32-person video calling last week.
WhatsApp Companion mode
As this screenshot shows, it’s simple to see if you can now link your existing WhatsApp account to a second phone by looking at the options on the registration screen for a “Link device” option. If you see this option, you may be able to use WhatsApp on another phone for the first time!

When you connect your WhatsApp account to a new smartphone, your conversation history will sync across all of your connected devices. Because this is a beta version, some functionality, such as the ability to check live locations and manage broadcast lists and stickers, may still be unavailable.
Users could link up to four devices to their WhatsApp account, allowing them to attach multiple phones. Whether you use WhatsApp from a linked phone or not, your personal messages and calls are end-to-end encrypted. When someone sends you a message, it is sent to all of your devices, so encryption is always maintained.
WhatsApp on Android Tablet
Through the 2.22.24.18 upgrade for WhatsApp beta on Android, some beta testers now have access to a presentation screen for WhatsApp on Android tablets.

After selecting the option “linked devices beta,” the new presentation page appears within the linked devices section, as shown in this screenshot. Since this feature is labelled “beta,” some users may still not be able to do things like check where live events are happening or manage broadcast lists.
Availability
In terms of availability, the “companion mode” and “WhatsApp on Android Tablet” features are rolling out with WhatsApp beta for Android 2.2.24.18, and it will likely take some time before common users can access them.