We typically say "papunta na ako". In the context of Philippine culture, it could also mean "I am just about to get ready and I'll arrive an hour after our scheduled appointment" because Filipino time. :)

Torusan is right, "Pauwi na ako" means that you're on your way home. But, I think, the more common version for "I'm on my way" is "Papunta na ako" (if you're still on the way but not so near the destination yet) or "Parating na ako" (if you're already near your destination).

"Pumupunta na ako..." would be more appropriate if it's a destination that's not "home". "Pauwi na ako" would mean that you're on your way home. I think it's more common to hear/say "Dumarating na ako." [I'm coming/arriving (shortly).]

Maraming salamat, Henry, very much "in depth" explanations !

“Pumupunta na ako doon” = I already (habitually) go there “Pumupunta ako dun” does not translate to “I am going there”. The present tense of the verb, i.e., “pumupunta*”, in this case only gives it the “I go there” or “I habitually go there” meaning. Adding “na” (already) to the phrase would mean that previously and for whatever reason you don’t go there, but now you already do habitually. “Papunta na ako doon” = I am already going/on my way/about to go there. “Pauwi na ako doon” = I am already going/on my way/about to go home there. (Destination is away from both speaker and listener) “Papunta na ako diyan” = I am already going/on my way/about to go there. “Pauwi na ako diyan” = I am already going/on my way/about to go home there. (Destination is where the listener is) * as mentioned earlier, we say “papunta na” and not "pumupunta" to give it the present or at-this-moment meaning.