Zello is an app that can be found on the Google Play Store, the App Store, and even on your PC. There is a free, personal use, version and a paid subscription version for business use.
This is a simple “walkie talkie” type app that utilizes WiFi or cellular data service to communicate with people around the world. There are many channels available for countless topics, including amateur radio groups. Granted, this is not a place where you’re going to make official “contacts” with other operators, but it may be useful for asking questions, getting information on projects you’re interested in, and setting up potential radio contacts. You may contact someone here from a state, or country, that you need confirmation on and set up an HF contact with them.
I’m not necessarily recommending this app, but rather sharing the information for it, in case anyone is interested in checking it out.