Login to your Reddit account and navigate to the link https://www.reddit.com/prefs/apps
Click on Create an app
Fill the required fields and If HOMEPAGE is the url of the homepage of your website save exactly the following url in the Redirect Uri option
If using Super Socializer plugin, save HOMEPAGE/SuperSocializerAuth/Reddit If using Heateor Social Login plugin, save HOMEPAGE/HeateorSlAuth/Reddit
For example, if your website is https://yourwebsite.com, you need to save https://yourwebsite.com/SuperSocializerAuth/Reddit or https://yourwebsite.com/HeateorSlAuth/Reddit in this option
Click on Create App.
Copy Reddit Client ID and Secret and save these at the plugin configuration page