Hi barton171-hotmai, thanks for joining the Community 🙂
You can edit this when creating an invoice on the web under the 'Message on invoice' field, or you can enter a default message on your invoice template by navigating to the Cog > Custom form styles > Edit > Content > Click the footer > See 'Message to customer on'.
When viewing the customer transaction list (Sales > Customers > Click on Customer to View), you should see a small cog symbol (settings) half way down the right side of the screen.
(on a PC - no idea if there's room on a phone/tablet screen)
Click on cog symbol & you can select the columns to view.
Make sure the Memo button is ticked.
You can then resize columns as required - but it should show the Memos from invoices & payments, etc.
Thank you for your reply. The memo field is ticked as per your instructions, on the customer transaction list it is showing the memo column but on the invoice it isn't there for me to write in :(