Our families live far apart. Can the enquiry (merisik) be done by video call or WhatsApp?

Yes; merisik is a custom for asking about intentions, and the Shariah does not prescribe how it is done. What matters is that good manners are kept. Let a respected person, such as the father or an uncle, contact the woman's wali (guardian) or parents, not the man directly contacting the young woman. Choose a suitable time and introduce yourself clearly: family name, where you live and your intention. Avoid sending long messages that feel like a questionnaire. Afterwards, follow up with a face-to-face visit when circumstances allow, especially before the proposal ceremony. Meeting in person between the two families is still important for building trust. See proposal (khitbah) guide.