Whitechain does not have any specific plugin, so you can use any EVM-compatible wallet.
If you added Whitechain (chain ID 1875) to your wallet before the migration, you do not need to change anything: the existing network entry now connects to Whitechain L2
For everyday signing, you can use MetaMask or Rabby. Reown (formerly WalletConnect) connects mobile and hardware wallets to dapps with a QR code or a deep link. For multisig treasury and admin operations, you can use Safe.
FAQ
Should I use a multisig?
For treasury and admin operations, yes. We recommend using Safe, where a transaction executes only after a set number of signers approve it (for example, 2 of 3), so no single key can move funds or change an owned contract alone. Each signer connects with their own wallet to review and sign.