Does any phone wallet support this anymore?? Is there a way to convert a private key to a seed phrase..?
AFAIK, multiple wallets still do. Electrum should be one of them. Exodus also allows you to sweep a private key from a paper wallet, and it also supports BIP39 (in case you have it encrypted).
This is not going to "convert" the private key to a seedphrase though. You have to create a standard wallet first, and when you sweep, the funds will be sent from the private keys/paper wallet address to that wallet.
The new exodus does not allow one to sweep a private key... :S there is no settings button to do it any more.. I am trying to sweep a dogecoin wallet.