How can I get a description to show in the memo box on a customers transaction list?

Hi graham21, thanks for posting on the Community

The memo field on the customers transaction list is linked to the 'message on statement' field on the transaction. 

It isn't possible to customise this view to pull text from the description field of the transaction. This is because the description field allows a high character count (up to 4000) and there can be multiple item lines on a single transaction, meaning there would be an overload of data on the screen. 

If you need to view the description, try running the Sales by Customer Detail report instead. Hope this helps!