The multi-sig UI is available for testing at
app.hyperliquid-testnet.xyz/multisig.
This is an advanced feature. Unlike most other chains, multi-sig is a primitive built natively into the Hyperliquid L1 instead of requiring smart contracts. Please read the Docs (
https://hyperliquid.gitbook.io/hyperliquid-docs/hyperliquid-l1/multi-sig) to understand the details.
Note that the UI is intended as a proof of concept for what interfaces can be built. For example, the multi-sig primitive supports all actions onchain even though the UI only supports a few.
As always, any bug reports are greatly appreciated.