A hag is a witch deeply entrenched in the art of dark magic. This kind of magic comes from experimenting with forces beyond our reality. Over the years, her abilities and spells grow in power. However, her physical form also changes, evolving into a higher life form. At the initial stages, she retains some resemblance to a humanoid form. As time goes on, it grows in size and all traces of humanity slowly vanish as she begins to resemble something close to an eldritch creature. Misshapen, formless, with tentacles, mouths, or limbs,etc, or what have you. Every new form is different from hag to hag.
Although powerful, they are not at the top of the ladder in terms of scale, and there are the authorities, who work in tandem with good covens, who seek to hunt then down and exterminate them. Some of these hags run the equivalent of fortune 500 companies, or are politicians in positions of power. Therefore, they must conceal their identity in the public sphere for the times when business must be conducted. Their changing form obviously poses some barriers for them, and must be worked around.
My first thought was some kind of glamour spell, which allows then to put on a false disguise to communicate with others. However, this doesn't take into consideration the size of the individual. A 9 ft (2.7 metre) tall human would be a dead giveaway, not to mention the increased weight of the hag, which perceptive people would notice. Also, there is always a feeling of wrongness that comes from an eldritch creature. They are so anathema to normal life, something from beyond this world and reality itself, that they ooze a sort of corruption that would be picked up by anyone who is in their presence for any length of time, and would figure out that something is wrong.
How can this creature remain in public life without exposing itself?