My mother has a headache mild, around the fronthead area, on the right side, I think is migraine in adults, treatment?

Maybe not migraine. This may not be a typical migraine, as the pain seems mild. Try over the counter products and/or hot or cold compresses to the affected area.
Have it checked out. This may be migraine or tension headache. If it is fairly new and frequent, it could be something more concerning. That's why she should see her doctor to rule out other causes and narrow down the type of headache. Generally, a headache can initially be treated with tylenol (acetaminophen) or Ibuprofen but this all depends on her other medical history and meds she's taking. After that, there are many options.