Error prevention is the principle that good systems should prevent mistakes, rather than trying to correct them after the fact. Gently guide your users through their journey by showing suggestions, providing smart defaults, and applying constraints where necessary (such as when filling out form inputs). At the same time, make it easy for users to change their minds throughout the journey.

Generally, there are two types of errors users make:

• Slips occur accidentally when you want to take one action but end up doing it wrong. For example, when you type "bisycle" instead of "bicycle." To prevent slips, you can use input constraints, provide helpful suggestions, or use forgiving input formatting.
• Mistakes happen as a result of conscious users' actions. They happen when users have wrong expectations or knowledge of how the functionality actually works. For example, when you want to click a button that is a non-interactive banner.