I use zoom for the video chat and had been using Microsoft Excel on a shared screen for the map and tokens.
But then one of my players told me about Owlbear Rodeo, a new free basic VTT that works like gangbusters for someone like me. Upload a gridded map (or use one of their basic blank ones), use the tokens provided or upload some of your own, cover the map with fog of war, then send your players the web address to load in. They then can move their own tokens around the map.
It is a simple and easy VTT that doesn't bother with adding in all the rules of 5E, it's just for easy mapping. As my players all have their characters on D&D Beyond, the easy map is all we need.