WhatsApp is the default for most NRI and expat families, since practically everyone back home already uses it for messages, voice notes, and video calls. For group video with better quality, Google Meet, Zoom, and FaceTime (if everyone is on Apple devices) are the usual choices, and Telegram is popular for larger groups and sharing files.
Be aware that some countries restrict or block certain calling apps, and voice-over-internet calls can be limited in parts of the Gulf, so check what actually works in your destination and have a backup app installed before you land.
Quality depends more on your internet than the app, so a solid home broadband or a generous data plan matters most. Keep an international calling option (through your carrier or a low-cost calling service) for reaching landlines and elderly relatives who are not on smartphones, and teach family a second app in case your primary one has an outage.