Apple’s FaceTime app for iPhone (and other Apple devices) is sufficiently popular that “facetiming” has become something of a generic term for video chatting.
With the release of iOS 15 from Apple, it’s now possible to use FaceTime on non-Apple devices including Android (and Windows). There are caveats. There is no FaceTime app for use on non-Apple devices. Rather an Apple device owner creates a weblink (easily shared via email or text message). Selecting that link will allow non-Apple device owners on Android (and Windows) to join a FaceTime conversation using a supported web browser (Chrome on Android or Edge on Windows). Other browsers may work also.
Apple’s sparse but accurate documentation is linked here: Create a link to a FaceTime call on iPhone - Apple Support. Though the documentation specifically mentions iPhone, the method is the same for an iPad running iPadOS 15. Support for creating FaceTime links on Macs will come with macOS Monterey (currently in public beta).
Otherwise, the closest thing Android has to a default (meaning it may already be on your phone) video chatting app is Google Duo.
Another popular option is the venerable Skype.
If you’re on Facebook, you might consider Facebook Messenger.
The great thing about these apps is all are available on iOS as well as Android, so you’ll be able to video chat with friends still using iPhones (with the caveat they use the same app you’re using).