First of all login to your twitter account
Then go to developer.twitter.com, select Apps from the menu, and click on the Create an app button.
Complete the application details form. You must enter an app name, description, website (this can be your website), and some information about how the app will be used. make sure that you checked the option : Enable Sign in with Twitter, and add your website url (this can be the folder where you installed Microncer) as callback url Then click Create.
After creating the app, go to Permissions Tab
Click on Edit Button
Check the option Request email address from users, then click Save
Go to Keys and Token tab, and you will find your app API key & API Secret Key