Yes, demo account will teach us about basic of forex trading. if we want to get maximal result in demo account, it will not be a guarantee for us to get maximal result in real account too. It depends our effort.
of course, we can learn many things from a demo account, with a demo account that will allow us to trade with the maximum. For that, try using a demo account with a well that will allow us to trade with the maximum and comfortable. since only demo account using virtual money it is very suitable to practice trading