From the Dashboard, click on Account and select Users from the drop-down.


 

In the Show Users Section, click on the Email Address of the User.

In the User settings page, click on the Agent Interface Options tab.


 

Click on Select Agent ACL and select your desired existing settings. You may also click on Create Profile if you want to create a new custom profile.

When using an existing Agent ACL, you may press the Edit Profile button to edit the User Agent Interface Options.

Scroll Down and look for Access to make a manual call to a transfer number:

Yes = Add a Transfer Button to External Numbers.

No = Default Setting. Transfer button is missing. 

Go back to Select Agent ACL and click the Save button to save the updated settings of the User Agent Interface Options.

Scroll down to the bottom and click on Apply Changes.