Autistic people often exhibit differences in attention. Sometimes they may have extraordinarily deep focus, while sometimes they may have difficulty concentrating.
In first case, autistic people can focus on one activity for hours on end. This is often related to a special interest. They may feel like they are "in a zone" and can be incredibly productive with their work. This extraordinary focus can be useful as an adult if they find a job that matches their special interests.
In the second case, autistic people may struggle to focus on anything. They may have difficulty transitioning in between tasks and starting new things. Other times, they may be constantly distracted by ambient noises and movement. This may be related to Sensory Processing Disorder. Sometimes this results in an ADHD/ADD diagnosis. In older autistic people, it may be a sign of autistic burnout.