I see three lines of thinking.

1. Send an email when you can find a WiFi connection. Will be episodic at best

2. Use a cell phone and share your location. It is more automated but you need connectivity. Coverage is far from perfect, so warn your loved ones that outages will be frequent.

3. Get some kind of transponder such as SPOT. It'll work (practically) reliably, everywhere. Battery life is measured in weeks. You can send emergency or custom messages. But it requires a device (probably close to 200$) and a subscription (close to 100).

If money is no object, a beacon is probably best. Otherwise, a roaming SIM and the occasional social media update might do.