To allow another of your devices to access ESPN+, sign in on that device with your ESPN.com account username and password.  If you have purchased ESPN+ via in-app purchasing on Apple, Google or Amazon devices, you will need to first link your ESPN+ purchase to your ESPN.com account in the ESPN App before you can access ESPN+ on other devices platforms.  You can create an ESPN.com account for free by clicking on the login link on ESPN.com.