A carriage return ends the current sentence or paragraph and places your cursor on the next line. Although most carriage returns are added by pressing "Enter" on your keyboard, carriage returns often propagate automatically when you import text from another source. These formatting inclusions frustratingly disrupt the flow of text, especially when editing, unless you remove all carriage returns.
Viewing Formatting Marks
Most word processors don't display formatting marks by default, so finding these invisible elements takes some finesse. However, comprehensive word processing programs, such as Word 2013, can display formatting marks to ease finding and editing them. In Word, check the Home tab for the Show/Hide button, which looks like a backwards P; clicking it toggles the formatting marks on and off.
Find and Replace
If you have multiple carriage returns, manually deleting them may not be practical. In such cases, you can use the Find and Replace feature that's included in most word processors. In Word, pressing "Ctrl-H" opens this utility, and you can select "Manual Line Break" from the Special drop-down menu to add this formatting element to the Find What field. If you don't see the Special drop-down menu, click "More" to see more options. By keeping the Replace With field blank, you'll delete all carriage returns when you click "Replace All."
In some cases, carriage returns may not be creating the apparent returns. Many word processor optionally specify spacing before or after each paragraph. Clicking the bottom left arrow in the Home tab's Paragraph group opens the Paragraph dialog and clicking the "Indents and Spacing" tab locates the spacing configuration. Changing "Before" and "After" in the Spacing section to zeros removes the extra spaces in any selected text.
Most word processors add blank lines between lines of text. Although it appears as though carriage returns are adding these extra lines, it's really just formatting. In Word, these options are found in the same Spacing section used to adjust paragraph spacing. Choosing "Single" in the Line Spacing drop-down menu removes the extra lines on any selected text.