Text boxes are flexible because you can place them anywhere on your spreadsheet.
You can link a text box to the contents of a cell.
(The link to the example file is at the end of the post.)
First draw a text box on your sheet.
Then when the text box is selected click in the Formula bar and type = then click on the cell to link to. You can link to a cell in other sheets. Changing the cell contents will change the text box contents. See image below.
This allows you to display dynamic messages around your spreadsheet. You can use IF functions in the formula in the linked cell to create a dynamic text message.
The formula in cell A5 in the above image is
The TEXT function formats values to use as text.
This technique is handy for dashboards where you may want to display an important KPI result in a large font size.
You can also use it to display validation messages eg “Journal is out of balance”.