To purchase lottery tickets online, visit the official website or app of your state's lottery, if available. After creating an account and verifying your identity, you can choose your preferred game, select numbers or opt for a quick pick, and pay through secure payment options like credit cards or e-wallets. Some third-party services also allow online ticket purchases for national and international lotteries, but it's important to ensure they are authorized and legitimate. After purchasing, your tickets will be stored digitally, and you'll be notified if you win.