On Windows you will need to download an SSH client. The most commonly used one is called PuTTY and can be downloaded from greenend.org.uk
Look for putty.exe under the heading For Windows on Intel x86.
##1. Add your Raspberry Pi as a host
PuTTY doesn't have an installer package, it's just a standalone .exe file. When you run it you'll see the configuration screen below:
Type the IP address of the Pi into the Host Name field and click the Open button. If nothing happens when you click the Open button, and you eventually see a message saying Network error: Connection timed out, it's likely that you've entered the wrong IP address for the Pi.
If you don't know the IP address, just type hostname -I in the Raspberry Pi command line. There are more ways to find your IP address here.
##2. Connect When the connection works you'll see the security warning shown below; you can safely ignore it and click the Yes button. You'll only see this warning the first time when PuTTY connects to a Pi that it has never seen before.
You'll now have the usual login prompt. Log in with the same username and password you would use on the Pi itself. The default login for Raspbian is pi with the password raspberry.
You should now have the Raspberry Pi prompt which will be identical to the one found on the Raspberry Pi itself.
pi@raspberrypi ~ $
You can type exit to close the PuTTY window.
##3. Modification, troubleshooting, and more
The next time you use PuTTY, look for the Saved Sessions section on the bottom half of the configuration screen. If you use this, we recommend switching to the Connection page in the left hand tree and setting the Seconds between keepalives value to 30. Then switch back to the Session page in the tree before you click Save. Using this setting allows you to leave a PuTTY window open for long periods of time with no activity without the Pi timing out and disconnecting you.
A connection might be unsuccessful due to various reasons. It is most likely your device or Raspberry Pi are not connected properly, SSH is disabled, you might have made a typo, or the IP address or credentials might have changed. In the latter cases, you need to update the host. For instructions on how to update a host and for further PuTTY documentation please see the PuTTY docs.