To Place a Drawing Boundary by Two Points

Select the Place Drawing Boundary tool.
(Optional) Select a detailing symbol style.
Select By 2 Points.
Enter a data point to define the first corner of the drawing boundary.
Enter a data point to define the diagonally opposite corner of the drawing boundary.
Enter a data point to define the location of the annotation of the drawing boundary.
Reset to place the drawing boundary.

Placing a Drawing Boundary by Two Points

If you place a drawing boundary in a DGNLib file, it can be used for placing named boundaries in your model.