The Stellar Memo is an additional address feature used to identify the recipient in a transaction.
The GMO Trust user dashboard has a Memo field on the Purchase and Swap (Ethereum to Stellar) pages. This Memo field is not mandatory. Please refer to the exchange where your Stellar wallet address was created to find out whether you need to provide a memo.
For Redemption and Swap transactions (Stellar to Ethereum), please use the Memo information shown on the GMO Trust user dashboard. Please be advised that the Memo information displayed on the GMO user dashboard is not entered within the GMO User dashboard, but from the third-party UI when sending tokens to GMO Trust.