Wi-Fi Proxy Settings
Go to Settings > Network & Internet > Wi-Fi. Long-press your connected network > Modify network > Advanced options > Proxy > Manual. Enter proxy hostname and port. Save. This only applies to that specific Wi-Fi network.
Per-App Proxy (Android 7+)
Some Android versions allow per-app proxy settings. Go to Settings > Network & Internet > Advanced > Proxy. Select which apps use the proxy. This gives you more control over what goes through the proxy.
Limitations on Android
Android system proxy only works for Wi-Fi by default (not mobile data). Apps can choose to ignore system proxy settings. Some apps like browsers respect it; others like social media apps may not.
Using a VPN App
For full-device proxy on Android, use a VPN app. This routes all traffic (Wi-Fi and mobile data) through the proxy. Popular options include WireGuard, OpenVPN, and commercial VPN apps.
Verifying Your IP
Open your browser and visit the IP Checker page. The displayed IP should show the proxy's location, not your actual location. If it shows your real IP, the proxy is not active.