Hello. I'm afraid I don't quite understand the question at hand. Are you saying that you created an Alexa Voice Service (AVS) device using a Raspberry Pi but that that device doesn't show up in your iOS / Android Alexa app under the "Devices" tab?
If that is the case, then it's possible that the Raspberry Pi and Alexa App are signed into two separate Amazon accounts.
If that's not the question at hand and you have some additional questions regarding integrating AVS into your Raspberry Pi, I would recommend reaching out the AVS SDK team by using the "Issues" tab of the "avs-device-sdk" GitHub repository here:
Recognizer start http message to AVS 1 Answer
Code base linking fails 1 Answer