user87497: I am using ledger and multi sig to sign a transaction I got signature hash where both party signed the transaction. How can I attached this signature to the transaction so that I can broadcast it to network?
any code reference will be welcome. Currently I am referencing electrum code.

user60443: 
How can I attached this signature to the transaction so that I can
  broadcast it to network?

This is more agnostic to any particular wallet software, but I hope it's helpful. When you sign a transaction, you then put the signatures in the scriptSig field of the input it corresponds to (the tx may have multiple inputs).
For a m-of-n multisig transaction, the scriptSig format is:
0 <sig1> ... OP_m <pubKey1> ... OP_n OP_CHECKMULTISIG
To broadcast it to the network, you can use the broadcast command in electrum:
cat signed.txn | electrum broadcast -

If successful, the command will return the ID of the transaction.

Alternatively you can use the sendrawtransaction RPC on a node running Bitcoin core.
sendrawtransaction "hexstring" ( allowhighfees )
Submits raw transaction (serialized, hex-encoded) to local node and network.

Also see createrawtransaction and signrawtransaction calls.

Arguments:
1. "hexstring"    (string, required) The hex string of the raw transaction)
2. allowhighfees    (boolean, optional, default=false) Allow high fees

Result:
"hex"             (string) The transaction hash in hex

Examples:

Create a transaction
> bitcoin-cli createrawtransaction "[{\"txid\" : \"mytxid\",\"vout\":0}]" "{\"myaddress\":0.01}"
Sign the transaction, and get back the hex
> bitcoin-cli signrawtransaction "myhex"

Send the transaction (signed hex)
> bitcoin-cli sendrawtransaction "signedhex"

As a json rpc call
> curl --user myusername --data-binary '{"jsonrpc": "1.0", "id":"curltest", "method": "sendrawtransaction", "params": ["signedhex"] }' -H 'content-type: text/plain;' http://127.0.0.1:8332/


87497: <p>I am using ledger and multi sig to sign a transaction I got signature hash where both party signed the transaction. How can I attached this signature to the transaction so that I can broadcast it to network?
any code reference will be welcome. Currently I am referencing electrum code.</p>
 60443: <blockquote>
  <p>How can I attached this signature to the transaction so that I can
  broadcast it to network?</p>
</blockquote>

<p>This is more agnostic to any particular wallet software, but I hope it's helpful. When you sign a <a href="https://en.bitcoin.it/wiki/Transaction#General_format_of_a_Bitcoin_transaction_.28inside_a_block.29" rel="nofollow noreferrer">transaction</a>, you then put the signatures in the <code>scriptSig</code> field of the <a href="https://en.bitcoin.it/wiki/Transaction#General_format_.28inside_a_block.29_of_each_input_of_a_transaction_-_Txin" rel="nofollow noreferrer"><code>input</code></a> it corresponds to (the tx may have multiple inputs).</p>

<p>For a m-of-n multisig transaction, the <code>scriptSig</code> format is:</p>

<p><code>0 &lt;sig1&gt; ... OP_m &lt;pubKey1&gt; ... OP_n OP_CHECKMULTISIG</code></p>

<p>To broadcast it to the network, you can use the <a href="http://docs.electrum.org/en/latest/coldstorage_cmdline.html#broadcast-the-transaction" rel="nofollow noreferrer">broadcast</a> command in electrum:</p>

<pre><code>cat signed.txn | electrum broadcast -

If successful, the command will return the ID of the transaction.
</code></pre>

<p>Alternatively you can use the <a href="https://bitcoincore.org/en/doc/0.16.2/rpc/rawtransactions/sendrawtransaction/" rel="nofollow noreferrer"><code>sendrawtransaction</code></a> <code>RPC</code> on a node running Bitcoin core.</p>

<p><strong>sendrawtransaction "hexstring" ( allowhighfees )</strong></p>

<pre><code>Submits raw transaction (serialized, hex-encoded) to local node and network.

Also see createrawtransaction and signrawtransaction calls.

Arguments:
1. "hexstring"    (string, required) The hex string of the raw transaction)
2. allowhighfees    (boolean, optional, default=false) Allow high fees

Result:
"hex"             (string) The transaction hash in hex

Examples:

Create a transaction
&gt; bitcoin-cli createrawtransaction "[{\"txid\" : \"mytxid\",\"vout\":0}]" "{\"myaddress\":0.01}"
Sign the transaction, and get back the hex
&gt; bitcoin-cli signrawtransaction "myhex"

Send the transaction (signed hex)
&gt; bitcoin-cli sendrawtransaction "signedhex"

As a json rpc call
&gt; curl --user myusername --data-binary '{"jsonrpc": "1.0", "id":"curltest", "method": "sendrawtransaction", "params": ["signedhex"] }' -H 'content-type: text/plain;' http://127.0.0.1:8332/
</code></pre>
