addmultisigaddress nrequired ["key",...] ( "label" "address_type" )

The addmultisigaddress RPC adds a P2SH multisig address to the wallet.

*bitcoin-cli help addmultisigaddress

addmultisigaddress nrequired ["key",...] ( "label" "address_type" )

Add a nrequired-to-sign multisignature address to the wallet. Requires a new wallet backup.
Each key is a Bitcoin address or hex-encoded public key.
This functionality is only intended for use with non-watchonly addresses.
See `importaddress` for watchonly p2sh address support.
If 'label' is specified, assign address to that label.

Arguments:
1. nrequired                      (numeric, required) The number of required signatures out of the n keys or addresses.
2. "keys"                         (string, required) A json array of bitcoin addresses or hex-encoded public keys
     [
       "address"                  (string) bitcoin address or hex-encoded public key
       ...,
     ]
3. "label"                        (string, optional) A label to assign the addresses to.
4. "address_type"                 (string, optional) The address type to use. Options are "legacy", "p2sh-segwit", and "bech32". Default is set by -addresstype.

Result:
{
  "address":"multisigaddress",    (string) The value of the new multisig address.
  "redeemScript":"script"         (string) The string value of the hex-encoded redemption script.
}

Examples:

Add a multisig address from 2 addresses
> bitcoin-cli addmultisigaddress 2 "[\"16sSauSf5pF2UkUwvKGq4qjNRzBZYqgEL5\",\"171sgjn4YtPu27adkKGrdDwzRTxnRkBfKV\"]"

As json rpc call
> curl --user myusername --data-binary '{"jsonrpc": "1.0", "id":"curltest", "method": "addmultisigaddress", "params": [2, "[\"16sSauSf5pF2UkUwvKGq4qjNRzBZYqgEL5\",\"171sgjn4YtPu27adkKGrdDwzRTxnRkBfKV\"]"] }' -H 'content-type: text/plain;' http://127.0.0.1:8332/