Upload via EpicWar link, eg: https://www.epicwar.com/maps/179039/

..or via Hive Workshop link, eg: https://www.hiveworkshop.com/threads/tkok-eastern-kingdom-3-3-0f.146077/

..or via Wc3Maps link, eg: https://wc3maps.com/map/167777/Legion_TD_Mega_3.44r

You can then load the map on bnet using: /w lagabuse.com .map Legion TD Mega 3.43
Check the full guide on custom map hosting.