Paul got his invitation to Google Fi and wants to know if he'll lose his ability to use ObiHai and VOiP. Leo says yes, probably. Leo uses Google Fi, and it can be used on all the new phones. At the bottom of fi.google.com, there is a link at the bottom to Google Voice and he'll have to link his Google Voice number to it. Leo likes it because it's extremely affordable at $20 a month for voice and text, and $10 per gig of data. You only pay for the amount of data you uses. Google Fi switches between Sprint and T-Mobile, depending on which service is stronger. But if Paul wants to save his Google Voice number, he'll have to choose it, otherwise, that Google Voice number will vanish.
Paul should check out the Google Fi FAQ for more information at fi.google.com.
Paul can transfer his Google Voice to another account to keep it as well.