How to track a family member (with permission)?

My sister is traveling abroad for a few months, and I'd love to track her for safety reasons (with her permission of course), knowing at least once per day where she is, with also the possibility to check when needed where she is exactly (GPS), ring the phone if needed etc (she has an iphone). I've seen the existence of "Find My", that seems to be an official Apple app to recover lost devices, and it mentions that you can follow family members etc. So I tried to create an apple account and install it in icloud.com, but I get an error saying that I need to have an apple device to use Find My in icloud.com. Is it possible to use Find My for this purpose without having myself an apple device? Or should I ask the password of my sister? If I want regular reports (once per day, needed if for instance the phone runs out of battery at some point, I may be happy to have the history), can I use some API to automatically query the position once per day?