user42587: Same question as What BIP32 derivation path does Electrum use? 
but for multisig. thanks.

user109222: Here's a descriptor for a 2-of-3 created by Electrum.
Receive addresses:
sh(sortedmulti(2,XPUB_1/0/*,XPUB_2/0/*,XPUB_3/0/*))

Change addresses:
sh(sortedmulti(2,XPUB_1/1/*,XPUB_2/1/*,XPUB_3/1/*))

(Replace XPUB_1, XPUB_2, and XPUB_3 with your three master public keys )

user42587: After a lot of struggle, I found out that Electrum uses following root derivation for normal and multisig wallets. For example:

root/0/0 for each cosigner. Example:

m/44'/0'/0' ==> shared root key (x)
x/0/0 ==> address for first receiving multisig (derive in all cosigners shared keys. all 3 keys must be lexicographically ordered).

some semi-compatible form of BIP45 for hardware wallets. Didn't test it but here's the code: https://github.com/spesmilo/electrum/blob/master/lib/base_wizard.py#L220

refs:
What BIP32 derivation path does Electrum use?
https://github.com/spesmilo/electrum/issues/2266
https://bitcointalk.org/index.php?topic=1819380

user3697: Electrum uses BIP45.
m / purpose' / cosigner_index / change / address_index
Example for non-change of the first cosigner and first address: m / 45' / 0 / 0 / 0
See: https://bitcointalk.org/index.php?topic=1634517.15
and
https://github.com/bitcoin/bips/blob/master/bip-0045.mediawiki

42587: <p>Same question as <a href="https://bitcoin.stackexchange.com/questions/36955/what-bip32-derivation-path-does-electrum-use">What BIP32 derivation path does Electrum use?</a> </p>

<p>but for multisig. thanks.</p>
 109222: <p>Here's a descriptor for a 2-of-3 created by Electrum.</p>
<p>Receive addresses:</p>
<pre><code>sh(sortedmulti(2,XPUB_1/0/*,XPUB_2/0/*,XPUB_3/0/*))
</code></pre>
<p>Change addresses:</p>
<pre><code>sh(sortedmulti(2,XPUB_1/1/*,XPUB_2/1/*,XPUB_3/1/*))
</code></pre>
<p>(Replace <code>XPUB_1</code>, <code>XPUB_2</code>, and <code>XPUB_3</code> with your three master public keys )</p>
 42587: <p>After a lot of struggle, I found out that Electrum uses following root derivation for normal and multisig wallets. For example:</p>

<ul>
<li><p><code>root/0/0</code> for each cosigner. Example:</p>

<ul>
<li><p><code>m/44'/0'/0'</code> ==> shared root key (x)</p></li>
<li><p><code>x/0/0</code> ==> address for first receiving multisig (derive in all cosigners shared keys. all 3 keys must be lexicographically ordered).</p></li>
</ul></li>
<li><p>some semi-compatible form of BIP45 for hardware wallets. Didn't test it but here's the code: <a href="https://github.com/spesmilo/electrum/blob/master/lib/base_wizard.py#L220" rel="nofollow noreferrer">https://github.com/spesmilo/electrum/blob/master/lib/base_wizard.py#L220</a></p></li>
</ul>

<p>refs:</p>

<p><a href="https://bitcoin.stackexchange.com/questions/36955/what-bip32-derivation-path-does-electrum-use">What BIP32 derivation path does Electrum use?</a></p>

<p><a href="https://github.com/spesmilo/electrum/issues/2266" rel="nofollow noreferrer">https://github.com/spesmilo/electrum/issues/2266</a></p>

<p><a href="https://bitcointalk.org/index.php?topic=1819380" rel="nofollow noreferrer">https://bitcointalk.org/index.php?topic=1819380</a></p>
 3697: <p>Electrum uses BIP45.</p>

<p><code>m / purpose' / cosigner_index / change / address_index</code></p>

<p>Example for non-change of the first cosigner and first address: <code>m / 45' / 0 / 0 / 0</code></p>

<p>See: <a href="https://bitcointalk.org/index.php?topic=1634517.15" rel="noreferrer">https://bitcointalk.org/index.php?topic=1634517.15</a>
and
<a href="https://github.com/bitcoin/bips/blob/master/bip-0045.mediawiki" rel="noreferrer">https://github.com/bitcoin/bips/blob/master/bip-0045.mediawiki</a></p>
