Google has made it possible to access your Windows desktop or your Mac from your phone, be that an Android phone or an iPhone. And it doesn't have to be iPhone for macOS, you can mix and match - all you need is the Chrome Remote Desktop app running on both devices.
Here we're using an Android phone and Windows 10, but the process is the same for an iPhone and macOS.
The first step is to install Chrome Remote Desktop on both your phone and computer. That's simple on a phone: go to the app store, search for it and install it.
On your computer, you will first need the Chrome web browser. If you don't have it, go to chrome.google.com in the browser that's already installed and download and install it.
Launch Chrome and type chrome://apps in the address bar at the top. Click Chrome Remote Desktop to launch the app, and accept the permissions it requires if prompted.
Now, click the Get Started button in the My Computers section and click the Enable Remote Connections button.
You will probably be asked to install the Chrome Remote Desktop Host, so follow the instructions to do so. If you find yourself staring at a 'Please wait while Windows configures Chrome Remote Desktop Host' for a long time, it's likely because it's waiting for you to accept the UAC prompt, so look for a flashing yellow-and-blue shield on the Taskbar, click it and allow the installer to make changes to your computer.
Once that's done, click the Enable Remote Connections button again. This time, you'll be asked to set a PIN code - a minimum of six digits. This stops anyone else from accessing your PC. And - if you're paranoid - know that Chrome Remote Desktop sessions are encrypted so no-one can see what you're doing.
You might be prompted to allow the app to make changes again, and will see a message to confirm remote connections have been enabled. There's also a warning to check the power management options to prevent your computer from going to sleep since, if it does, you won't be able to connect to it remotely.
To access your PC from your Android phone, launch the Chrome Remote Desktop app that you installed on it earlier. Make sure you're signed in with the same Google account as on your desktop PC, otherwise your computer won't show up in the list.
If it's greyed out, your PC might have lost its internet connection, but if all is well you should see the name of your computer appear in the app: tap on it and enter the PIN you set earlier to begin the session.
Once these steps are followed, it's possible to access your desktop remotely, or even authorise someone else to do so by sharing a code -- a nifty way to have a relative troubleshoot your computer when they're on the go.
How to control Windows from Android
When you're connected, you should see some or all of your Windows desktop. You can pinch to zoom in and out, which you'll probably need to do to click on smaller things.
If you want to move a window, long-press on its top bar, then drag your finger to move it.
Your phone's touchscreen will control the computer's cursor. This means it will work as the computer's trackpad. If you'd prefer it to work like a touchscreen so you can tap on things directly, rather than having to move the cursor over the item first, swipe down from the top of the screen and tap the mouse icon and it will change to a finger. Tap again to change it back to mouse control.
Click in a text field and the smartphone's native keyboard will pop up. It's a simple way to make small edits when you're on the go. If you wanted to type text in a Word document, you might have to bring the keyboard up manually, so swipe down from the top of the screen and tap on the keyboard icon.
You can also send the Ctrl-Alt-Delete signal to the remote computer by tapping the three dots next to the keyboard icon. This might be needed to bring up the login screen to enter the Windows password. It's also where you'll find the Disconnect option to end the session.