RPGMemes

You've gotten some good advice, but I want to add that if you're feeling masochistic you can use the discord bot Avrae to do your maps in discord chat.

Joking aside, Avrae is great and I really recommend you check it out if you aren't using it... but using it for maps is kinda miserable. Using a dedicated virtual tabletop like Owlbear Rodeo will serve you much better.