Do both parties need What'sapp installed to have a phone conversation?

[AC Question]

Can I use what's app on my android smart phone to make calls to any phone or must the other party also have What's app installed on their phone?

 

[Javier P]

Welcome to the forums. Yes, you need the app installed in both phones.

 

[ManiacJoe]

If you use the regular phone service on your phone, then no one needs any special software.

If you want to use the WhatsApp data system to make the phone call, then both you and the other person need to be using the WhatsApp data system via the WhatsApp app.