Windows
Easiest method
Settings → Network & Internet → Wi-Fi or Ethernet → your network → IPv4 address
Fast command
ipconfig
See your public IP instantly and learn how to find your local IP address (private IP) on any device.
Your local IP address (private IP) is your device address inside your network (for example 192.168.x.x or 10.x.x.x).
Settings → Network & Internet → Wi-Fi or Ethernet → your network → IPv4 address
ipconfig
System Settings → Network → Wi-Fi (or Ethernet) → Details → TCP/IP → IP Address
ipconfig getifaddr en0
Settings → Wi-Fi → your network → Details → IP address
Settings → Wi-Fi → (i) on your network → IP Address
hostname -I
If you see several, your LAN one is usually 192.168.x.x or 10.x.x.x.