Zahramay Falls is the home to Shimmer & Shine along with other genies & sorceress. Although normal humans are not allowed to visit Zahramay Falls, Leah & Zac were given exception by wearing genie outfits to blend in. When they ready to leave to go back to their human world and come back to Zahramay Falls also Shimmer and Shine calls Leah and Kaz call Zac in a special chant if they need them, they would rub the Leah's bottle and Zac's lamp, the magic carry them, get inside then the bottle and lamp goes poof. While Leah and Zac through the portal, the magic will change back to the normal clothes when they go back home and change back to the genie outfits when they go back to Zahramay Falls. How ever, this is only a prediction since we never saw this on camera.
Zahramay Falls located to the other world and currently the portal is inside Leah's genie bottle and Zac's genie lamp.