In the early days of printing presses and typeface blocks, letters that would otherwise look strange or take up too much space when placed side-by-side were carved together on the same block. Called ligatures, these interacting letter combinations optimized the rest of the line's spacing and improved the overall readability of the word or the sentence. Adobe InDesign automatically inserts ligatures -- provided the font is designed to support them -- although this setting can be disabled when the feature is unnecessary or unwanted.

Character Panel
Step
Expose the Character panel if it isn't already open by clicking the "Window" menu and selecting "Type" followed by "Character."
Step
Use your cursor to highlight the text from which you'd like to remove the ligatures.
Video of the Day
Step
Expose the Character panel's "Options" menu. It is a small downward-facing arrow and four horizontal lines located at the top of the panel.
Step
Click "Ligatures" -- which, if enabled, has a check mark beside it -- to disable the feature.
Control Panel
Step
Use your cursor to highlight the text containing the ligatures.
Step
Click on the "Options" menu icon, which is located at the far right of the Control Panel and looks like a small downward-facing arrow and four horizontal lines.
Step
Click "Ligatures" to uncheck and disable the option.