ADHD (attention deficient-hyperactivity disorder) is a neurodevelopmental condition which comes with a multitude of challenges for the individual who has it. It's UNDER-diagnosed in females due to girls "masking" a whole host of symptoms in order to fit in socially. Girls will internalize the sometimes crippling feelings vs externalize like males--this can make it very tricky to spot in girls.
It's a executive DYSfunctioning problem, The executive functions are responsible for behaviors such as time management (always late?), ability to organize (messy room?), mood regulation (meltdowns?) and working memory (you child forgets what you JUST told them? They always losing stuff?). It's also a brain chemistry issue (lack of to be exact)---dopamine and norepinephrine are two neurochemicals that are responsible for frustration tolerance, focus, decision making and many other brain functions. So are you beginning to see that it's not about being "lazy or spacy or moody" or any other negative words used on your child? ( which affects their self esteem greatly BTW--we can be VERY sensitive...it's that pesky rejection sensitivity ). ADHD also has a genetic component (generally one or both parents have it) It's also not a lack of focus, it's more a issue with how we focus and on what (yes, I too have ADHD)
I generally recommend that when a parent starts to see the aforementioned behaviors consistently seek help via a NEUROLOGIST for an accurate diagnosis, then reach out to a mental health practitioner who either has strong working knowledge or has ADHD as one of their specialties. (like me!)
Remember, it's not something that your child will "grow out of"--but like any other condition, it CAN be managed and your child can grow up to be a healthy, happy and functional adult.