I had a Join Shared Wallet. I can see my BTC; but my partner can´t because she lost the back up words. We aere trying to send this to an other wallet but it´s imposible if the other account doesn´t authorized it. What can I do for recovering these wallet?
Assuming this is a 2-of-2 multisig shared wallet, it is not possible to do anything with the coins without signatures from both wallets. Bitcoin uses strong crytography, and when signatures are required, they're really, really required. That's why it's secure.
If your partner has irretrievably lost the wallet and backup phrase, then the two of you have irretrievably lost the coins. Sure, you can see them, but you'll never be able to spend or transfer them.