Messenger for Discord

You must be admin of the channel/server to see webhooks. Pop into server settings, click on Integrations, and click on Webhooks. From here you can either create a new bot user, or give it the webhook URL of an existing one. This is also accessible by right-clicking a desired channel, and clicking Edit channel. It's recommended to setup a mod/admin-only visible channel and grab the webhook for that to test the functionality out without notifying your Discord server users.