With your cursor positioned at the line to be adjusted, or with the entire text box selected (will globally change all lines in text box), go to FORMAT LINE SPACING.
This brings up the Line Spacing Dialog which has three settings that can be adjusted.
(1) Adjusts the distance between the lines of a paragraph.
(2) Adjusts the distance between the start of this paragraph and the one above it (separated by a hard return).
(3) Adjusts the distance between the last line of this paragraph and the one below it (separated by a hard return).
-Troy @ TLC