If you’re using the web app: You can make voice calls to your contacts by simply expanding the Contacts field present on the left-hand side of the screen. Tap on the first icon in green to initiate a voice call. Or you can open Contacts from the onship homepage, and then tap on the Call icon in green present next to the phone number of the contact.
If you’re using the mobile app: Tap on the Contacts icon from below, choose the contact you want to make a voice call to and then tap on the second icon in green. Or you can simply click on Home icon > Tap on the desired contact > Tap on the second icon in blue present in the top right-hand corner of the screen.