You can check your external IP address by opening your Web browser and direct to a website like http://whatismyip.network/. You can also write "IP address" in Google to see your IP address. IP address isn't mainly secret, and it's observable by any webpage or other online service you visit. . Still, your IP address isn't essentially publicly linked with you, and you might not need to share it too broadly for safety reasons.
In case someone asks for your IP address, you should ensure why they're asking and that you feel like telling them about it, just as you would not probably like to give your phone number, home address or email address to anyone who asks for it. By doing that you would be able to find out your IP address.