most countries supporting bitcoin systems are estonia, they seem willing to implement innovations such as blockchain technology for health care, banking and even governance by allowing citizens to be "E-resident." The service also gives Estonian citizens and digital authentication businesses. It is also one of the first to use a blockchain-based e-voting service that allows people to become shareholders on the Tallinn Nasdaq Stock Exchange.

countries that support the next bitcoin are the United States, Denmark, Sweden, South Korea, the Netherlands and others.

for more details please read here https://news.bitcoin.com/worlds-top-10-bitcoin-friendly-countries/