When using a text overlay, how do I create a white rectangular border around text

If you just want to create a box outline around the video, open the title in the Title Adjustments area by double-clicking it on the timeline and customize your text on it. Then:

1. Select the Shapes tab on Title Adjustments panel. Select the rectangular shape and drag in to create a rectangle over your text.

2. With the Selection Tool, click to select the rectangle and, this is very important, go to the Style tab and apply a text style to the rectangle that includes a stroke or outline. Birch White 80 will do.
3. With the rectangle still selected, go back to the Shapes tab and click the little artist's palette button on the Title Adjustments panel to open the Color Picker.4. On the Color Picker, select Fill and then click the "/" button on the color picker to make the rectangle transparent.

5. Click the Fill button and set the Stroke width and color for the stroke or outline around your rectangle.

Do you want your text to appear inside a white box or within just the outline of a box?