Get the extension What is a memo or destination tag?
A memo is a short note attached to a payment on Stellar and the Cosmos chains; on the XRP Ledger the same role is played by a number called a destination tag. Exchanges use one shared address for many customers and rely on it to credit the right account.
Why it matters
Forget it when depositing to an exchange and the funds reach the exchange's address with no owner attached; getting them back means a support ticket at best. On THORChain the memo is not a note at all: it is the instruction that tells the protocol what to do.
How Locker Protocol Wallet handles it
Locker Protocol Wallet lets you enter the memo or destination tag when you send, and the Vault shows it as part of the payment before signing, so a missing or wrong one is visible before the funds leave.
Questions
Do I need a memo to send to my own wallet?
Usually not. Personal addresses do not need one; exchange deposit addresses usually do, and say so on their deposit page.
What if I sent funds without a memo?
Contact the exchange's support with the transaction hash. They can often credit it by hand, but it can take days.