What are employees experiencing if they are motivated by finding fulfillment in their work?

When employees are motivated by finding fulfillment in their work, they are experiencing intrinsic motivation. Intrinsic motivation comes from within the individual and is driven by personal satisfaction, the enjoyment of the task itself, and a sense of accomplishment. Unlike extrinsic motivation, which relies on external rewards such as money or recognition, intrinsic motivation is rooted in the inherent interest or pleasure in the activity.

References

Managing Human Capital Textbook

"Drive: The Surprising Truth About What Motivates Us" by Daniel H. Pink

SHRM (Society for Human Resource Management) guidelines on employee motivation