You need to pass one additional exam to receive the MCSD App Builder certification in addition to 70-480 and 70-486. Here is a good explanation:
https://buildazure.com/2016/10/20/mcsd-app-builder-certification/
Thanks,
Sam Lester (MSFT)
https://blogs.msdn.microsoft.com/samlester/
Twitter - @SQLSamLester
This posting is provided "AS IS" with no warranties, and confers no rights. Please remember to click "Mark as Answer" and "Vote as Helpful" on posts that help you. This can be beneficial to other community members reading the thread.