How to make a Hidden walle to NON HIDEEND?

you said you are doing some kind of “conversion” all the time

Yes… sorry. I use wrong word.

I can convert the key to a passphrase. I do this every time I generate a wallet.

I mean
I can convert the key to a MNEMONIC. I do this every time I generate a wallet.

He said wallet was in metamask, then he reinstalled it and now it is not there.

and this is nothing about lost mnemonic or passphrase

yes, it is, you need correct passphrase to see the same wallet/address

you are not converting anything you are using your private key which is always same and you are adding passphrase…which is how this whole thing works…or I just don’t understand what you are doing because you still did not explain exact process/tool…

this is specified in BIP-39 (for Single backup): bips/bip-0039.mediawiki at master · bitcoin/bips · GitHub

and in SLIP-39 (for Shamir backup): slips/slip-0039.md at master · satoshilabs/slips · GitHub

you are not converting anything
How wallet know my private key if it not convert mnemonic to key?

yes, it is, you need correct passphrase to see the same wallet/address

you took my quote out of context