Constraint settings include options for on-screen constraint prompts and turning inference constraints on or off. These settings are available on the Editor Settings dialog box, on the Constraints tab.
For detailed steps, click the corresponding link described in the following table.
On-screen constraints prompt you to provide direction and distance as you draw segments for line and polygon features.
Inference is a constraint mode that uses your current snap settings to snap the pointer to inferred geometric relationships between the current vertex and existing feature geometry.