You can try the following methods to find out if someone has called you from a VoIP number:
Use a website that allows you to look up the LRN or Location Routing Number, and the search will tell you who the carrier is. You can then look up the carrier to see if it is a regular or VoIP service provider.
Look up the number using reverse phone lookup websites. The search will show you if it is a VoIP number and other details.
If you are a VoIP user, you can ask your provider to tell you more about the caller by doing a CNAM lookup. However, this is possible only if the caller uses a registered ID.
VoIP numbers usually have two parts - a caller ID (the number you can see) and a CNAM. Configure your device to display both the caller ID and the CNAM.