Hi,
CTR refers to the ratio of people who clicked your ad when viewing it.
I can't really comment on whether the CTR is a good one as it depends on several factors (the most basic one being the product or service being marketed. For eg:- An ad offering a discount at a popular restaurant will tend to have a greater CTR than an offering for say a dental consultation coupon).
Let me know if you have further questions.
Also, kindly specify the Adobe product you are using.
Kind Regards
Rahul