I cannot add text to my iMovie

Are you saying that you are not getting the template shown below in which you can type the text?

If so, try deleting preferences and see if that cures it. To delete preferences open iMovie while holding down the Option and Command keys and select to delete preferences in the box that appears. iMovie will open in a new library. Reopen your old library to get back to your projects.  Deleting preferences is a safe procedure that will not cause data loss or disruption to your project.

-- Rich

What steps are you doing to add text and what happens when you try?

-- Rich

Try the deleting preferences procedure that I described in my previous post.

—Rich