RichTextEdit controls
The RightMargin property specifies the size in inches of the right margin on the printed page.
Enter the desired size in inches in the Right Margin field of the Document tab page of the RichTextEdit control’s property page.
The RightMargin property takes a long value.
The following line sets the right margin of a RichTextEdit to 1 inch.
rte_1.RightMargin = 1
To set the right margin: