If you're going to call a prospect, you have to leave a message. Regardless of whether the prospect was actively screening calls or simply away from their desk when the phone rang, your number will pop up as a missed call. And if there's no accompanying voicemail? Well, it must not have been terribly important.
You can also use the Slydial app for iOS or Android. Create a free account with the service, then choose a contact through the app or manually enter a phone number. Once the app has connected the call, leave a voicemail, and hang up when you're finished.

To access voice mail settings in the new Outlook on the web, select Settings > View all Outlook settings > General > Voice mail.
Calling leads is an important part of growing your business, but it can get frustrating when you call and call and never get a reply. Having phone scripts in place can make all of the difference in the effectiveness of your lead calls. Scripts allow you to come across as confident and professional and convey all the important points you need to make. No more stumbling over your words or forgetting to mention an important factor, like your name or phone number. Scripts will help you stay consistent and make calling more enjoyable because you’ll know what works and what doesn’t.