WhatsApp has announced that it will soon start sharing your personal details with Facebook. This will enable Facebook to show you targeted ads, friend suggestions and more. These “to be shared details” may include your phone number as well. If this is too much for you and yo don’t want WhatsApp to share your details with Facebook you can do so.
When WhatsApp shows you the new “Terms & Agreements” (first screenshot shown above), don’t tap on agree. Tap on read and then uncheck the box that reads “Share my WhatsApp account information with Facebook”.
In case you have already tapped on agree, you can still opt out. Go to (Second screenshot shown above) Settings—>Account—>Uncheck “Share my WhatsApp account information….” and yo are done.
Using either of the methods written above you can opt out of WhtasApp sharing your info with Facebook on Windows 10 Mobile or Windows Phone. The new terms and agreement, account settings are available on new WhatsApp Beta and may be coming to the stable version soon.