How to add Twitter login and registration to WordPress
A Twitter account is required in order to add Twitter login and registration to your WordPress website. Navigate to https://developer.twitter.com/en/apps and click on the "Create an app" button.
You'll now be redirected to page where you need to configure the details of your Twitter App. Make sure the the settings highlighted in the screenshot below are all filled and/or enabled, otherwise your app will not work properly.
Make sure the setting "Enable Sign in with Twitter" has been enabled.
Within your Twitter app, navigate to the "Keys and Access Tokens" tab and copy and paste the API Key and API Secret keys into your WordPress website.
In your WordPress dashboard, navigate to "Settings → Posterno → Accounts → Social login" and fill in the Twitter API Key and Twitter API Secret settings, with the keys that you've just retrieved.