It depends on your subscription plan!
Free trial accounts can monitor up to 10 keywords at a time. With a Personal Plus plan, you can monitor 5 keywords, Professional Premium comes with 10 keywords and Professional Max users can monitor up to 20 keywords.
If you need a custom plan - we can make that happen, please reach out to our Customer Success Team :)
If you are logged into Brand24, you can check your current limits here.