Try putting a hard return at the end of the last line
I think it is control return

What application are you working with? Is this Excel or Word? And yes, I like Sami's suggestion. Either Ctrl+Enter or Shift+Enter, or maybe even Alt+Enter, I don't remember which. But a lot of times, I know Excel, for example, will truncate that last character, so it might not be possible.

This is an Access database.

The hard return works in the original form. But I have another form that uses this Field (Description) but it doesn't Stop the extended last line on the second form.

Do you have the text box set to rich text?

No they are set to plain text on both.

OK, I see what you're saying. I'll look into it for you. Give me a bit.

You said you have another form that this works in. I'd like to see a screenshot of that, please, because I can't figure out how to get it to work at all, no matter what I do. That last line, if it's only got a couple of characters in it, gets stretched out like you've shown me here. I've got a possible solution, but it involves manually adjusting that last line after you're finished editing it. However, I know you're looking for an automatic solution. It's just difficult because there's no easy way for Access to tell how many characters are in that last line.

If we could set the text box to a monospaced font like Courier, where we know how many characters go across in a line, then I can come up with an easy solution for you. But with a proportional font, it's very difficult to do. We could estimate, but the estimates aren't always right.

I am sorry for the late reply, but life happens. Anyway the screen shots above show the two forms that are involved. Do you need to see them in form view as they are both in design view above. What I do is enter the data on the first form and use that data to fill the fields on the second form.

I have set the text box to a monospaced font.

I've got a solution for you. It's not elegant but it works. I'll be making a video about it shortly.

Here ya go. Took me a bit, but I think it's a decent solution: Distribute Text