WhatsApp

It is possible to use WhatsApp to hold videoconferences, but calls are still limited to four people and can only be made via mobile phone.

To start a group call, open the group's chat tab and tap the call icon in the upper right corner of the screen. Once your contacts list launches, choose the person that you want to add to the call. You can add up to three people to your call. Then, click the camera icon

To add people who are not in the group, select a contact and open the chat tab. Tap the camera icon in the upper right corner of the screen. Once the call gets connected, check for "Add person," which looks like a small figure with a "+" sign in the upper-right hand corner of the screen.

Skype

This is one of the most popular video conferencing apps. In addition to video and audio calls, it also enables you to share your computer screen to present something to other participants. Group video calling for up to 50 people is available for free with the Skype video chat app, but you can also sign up for a business plan (Skype for Business).

To use this feature, you need to download Skype on your phone or tablet from the app store or the internet (to try Skype on your computer without downloading, go to web.skype.com). You will have to create an account. If you already have a Microsoft account (@outlook or @msn), you are already registered as a Skype user. Just open the app and login. Once logged in, just type in your friends’ names or e-mails and start a call.

Google Hangouts

Those who already have a Gmail or a YouTube account may prefer this option, which allows you to connect up to 10 people.

If you already use Gmail, look for the Hangouts icon in the bottom left corner, below the list of folders (where your profile appears). Alternatively, you can go to hangouts.google.com or download the mobile/tablet app from the app store.

It is possible to search for friends among your contacts (people with whom you have already exchanged e-mails via Gmail and your contacts on Android phones are already registered automatically) or send them an invitation to join the tool. Then, tap "Video Call".