I have lost my iphone and need help on tracking it?

Follow these steps: https://support.apple.com/en-us/HT201472

In addition to the support article muguy has provided you, there are, at least, three critical things that need to happen in order for you to have any chance of finding your lost iPhones:

1. You must have enabled "Find My" BEFORE they were lost.
2. The phone must have sufficient charge left and be powered on.
3. The phone must be connected to the Internet, either by Wi-Fi or cellular.