By now, you might be aware of NPSettings. In-case if its new to you, read this post.
In your Unity project, If Twitter is not enabled, enable by below steps. 1. Open NPSettings and select Application Settings. 2. Under supported features section, Enable Uses Twitter checkbox and Save (see button at bottom).
Once you have Twitter feature is enabled, select Social Network Settings. Let us take a brief look into it:
Consumer key from your twitter application configured in dev.twitter.com
Consumer Secret key from your twitter application configured in dev.twitter.com