I created a small and smiple todo list app. fast and efficient https://besttodolist.netlify.app/
Using click event. I created a function that takes in the input value and then creates an li element to add it to the ul in the HTML. Every li thats being added it's also giving a class with a click event as well. when that li that was created through the click event is clicked by the user it adds CSS. When the user finishes the task they will click on the li and it'll get cross out. There is another click event for li that has been crossed out. This function will then remove the li from it's ul.
No matter what your experience level, being an engineer means continuously learning.