It's easy to use the internet to make phone calls, both national and international, for free - as long as you have an internet connection and some software. There are options for both smart phones and computers. You may even have this facility without realising it.
There are a range of options to choose from - select the one that you find easiest to use.
I have friends and family scattered around the world, and WhatsApp is my favourite way of phoning them. I have the app on my phone, and use it to send texts, make phone calls, video calls, and to send photos and video files. It is easy to use, very reliable, and very effective. You can set up groups of people to communicate with or contact individuals. As long as you have the mobile numbers, you can contact them.
One of the many features included with your gmail account is Google Hangouts. This facility allows you to have both voice and video calls, and if you have a gmail account, there is no setting up or installation, unless you want to have it on your phone. I have used it successfully for group conference calls, and the ability to chat and share your screen - which could have your presentation on it- during the call make it a brilliant tool for business calls and presentations. It is simple to use, and reliable.
Skype has been around for a while, and if you have a Microsoft computer, you will have it already installed. You will have to create a Skype ID to use it, and this ID needs to be shared with anyone you want to contact. The irony is that it can be tricky to find your Skype ID when you have set up the account. I have used Skype for interviewing staff, and for personal calls, but while it is functional, I have found it to be unreliable at times, and it lacks some of the functionality of Google or WhatsApp.
If you have facebook, then Messenger comes with it, although you do need to agree to use it on your smart phone. This app allows you to send text messages, images and videos to your contacts on Facebook. Like WhatsApp, it is very easy to use. It also allows you to make phone calls to your contacts. I tend to use the messaging option far more, which I like, particularly as it integrates with so many other tools I use, so it's simple to share links and information.
WeChat is an app that works with both your phone and computer. You use your phone to log into the program on your computer. If you're not tech savy, this option is more tricky to set up. However I do contract work for a Chinese company, and there are many internet restrictions in China. WeChat is an option they can use, and I have had videocalls and sent texts with WeChat. It works well, and offers a reliable service.
I am about to start using Zoom, which allows for Video calls. Again, this is the service I will be using for my work with the Chinese Company.
If none of these work for you, you might like to try Viber, which is highly rated, but is not a program or app that I use.
There are so many ways the smart use of technology can make our lives easier. The trick is to use it to your advantage.