I have shared before you can link a textbox to a cell and have a customised message delivered via the textbox. But there is something else I recently learned from Wyn Hopkins (MVP) about this technique.
In the images below I show how to link the textbox to cell A6.
With the textbox selected click in the Formula Bar and use the mouse to click on the cell to link to (A6) and press Enter.

Changing the report updates the textbox.

Something new
All that I have shared before, but what I recently learned was that you can still type in the textbox after linking and it remains linked to the cell and still updates.
You can click inside the textbox and press Enter to insert a line and type away – see image below.

It remains linked – so changes still update.

You can type below the entry too!

