In form design, where should writing line captions be positioned within the box?

Positioning the writing line captions in the upper lefthand corner of a form design is effective because it is a standard practice that aligns with the way users naturally scan and process information. Users tend to read from left to right and top to bottom, so having the caption in the upper left helps the user quickly identify what information to input into the corresponding line.

This placement also allows for a clean and organized look, making it easy for users to associate the caption with the input line directly beneath it. By placing the caption here, it becomes prominent yet unobtrusive, facilitating a smoother data entry process. Additionally, this convention is widely recognized among users, enhancing familiarity and ease of use when interacting with forms.