Thank you for the opportunity to help you with your question!
Both theorems and postulates are statements of geometrical truth, such as All right angles are congruent or All radii of a circle are congruent.
The difference between postulates and theorems is that postulates are
assumed to be true, but theorems must be proven to be true based on
postulates and/or already-proven theorems.
Please let me know if you need any clarification. I'm always happy to answer your questions.