What is the difference between an astronomer and an astrophysicist

Not much. It used to be that astrophysicists used more physics, but the truth is you can't just publish observational papers any more - everyone needs to be able to interpret their work using math, physics, and computational methods. Every astronomer has a strong physics background, so often it's simply a convention - stellar astronomy vs galactic astrophysics vs solar physics. What we always tended to call it is more what it's considered. But many people who call themselves astronomers have degrees in physics.

an astronomer looks only at the surface of stars and distinguishes the type of star, etc.by visual analysis of the surface. An astrophysicist studies the intrinsic nature of a star, including its surface and its inner workings. Astrophysicists like to know what makes a star tick !!

Not all that much these days. Many in the field are often a mix of the two at some time in their careers. That said, there are differences in the job description.
Astronomers are the people who actually go into observatories to look at the sky at night and record data.
Astrophysicists are more theoretical in their approach and need not get any more hands on with observation than sitting in their university offices!
To put very simply, astronomers observe and record stellar data, the astrophysicists then do the maths, and work out from this data exactly what is going on and what causes the observed phenomena to occur.

astronomer = studies objects in space
astrophysicist = studies properties of light and motion and interaction between objects and forces in spaces