Automating a task in a browser

I have a task to delete 1000+ users from a Learning Management System. This LMS is hosted in a different site and I need to enter every username and edit the person to delete him/her. Is there any method to automate this process i.e. to automate deleting the user process in a browser? I can feed in the usernames in a txt file to a particular location/application and then the system automates the task; inorder to save time. Thanks.