Find My is only available for Apple devices – including iPhones, iPads, and Macs with T2 or Apple Silicon chips. If you're asking how to get the feature on an Android phone, don't hold your breath waiting for Apple to help Google out by giving away the feature. Check with Google about what they provide (if anything) for Android.
If the issue is that you've lost an Apple device that supported Find My, and had Find My turned on, and you don't have another Apple device with which to mark it as Lost or to track it, you can use the Web interface to Find My.
https://www.icloud.com/find
Likewise, there's a Web interface to iCloud. If you were using iCloud Photos, even with just a single Apple device, the Web interface might give you a way to download copies of your photos to a PC, Mac, even a Chromebook.
https://www.icloud.com/