To log in to GPT-4, visit the OpenAI website and access the login page for ChatGPT. If you already have an OpenAI account, simply enter your registered email and password. For first-time users, you will need to create an account by providing a valid email and setting a secure password. Once logged in, you can start using GPT-4 for a wide range of tasks, from answering questions to generating text. GPT-4 is designed for more advanced interactions, offering improved understanding and conversation. Enjoy seamless access to one of the most powerful language models available today.