What do I say about why I left my last job?, insurance claims processor here

They always ask why I left, and I freeze. This is my first time dealing with any of this. I do not want to blame the company. Do they ask follow-ups?

Say it plainly and move on to what you can do. Interviewers usually move on if you do.

Practise it out loud with a friend. Mine felt natural after the third try.