The multisig option is a unique option. Many other blockchain wallets do not have the technology/knowledge to implement this feature as NEM uses multisignature contracts over multisigged accounts. It basically lets you make a normal wallet and then multisig it. At that point, the account has no power and its private key is useless. You then need multiple keys from other singing accounts to send XEM. Any m-of-n combination can be made, meaning 1-of-1, 1-of-2, 2-of-3, 10-of-10, etc. The images below will explain the principle.

In above picture the private key of the multisigged account is nulified. Alice, Bob, and Chuck have custodial control over Account M.

With only a few clicks, Chuck’s account is added and Davie’s account is removed.

The best part of NEM's multisig solution is it can be set up by anybody in less than a minute with just a few clicks. Later, additional accounts can be added or taken away, or the minimum number of signers can be edited with just a few more clicks on the mobile wallet, or any other NEM wallet as multisig is supported across all platforms.