Note: For more information about this topic, see Borders and lines.
In a letter, a line is often drawn between the footer and the body text.
On the ribbon tab Home | group Paragraph, you will find the Borders button 
. This allows you to add a complete border or individual border lines to the left, right, top or bottom of a paragraph.
To insert a border line above the footer, set the cursor in the first line of the footer. On the ribbon tab Home, click on the black arrow next to the Borders icon for the dropdown menu and select Top.
The paragraph should now be displayed with a thin black line above it.
Normal text paragraphs can be furnished with lines via the same method as for footers. This also works for some types of objects, such as table cells.