No indentation

I noticed that I could not add indentation or spaces (i.e.  )
in my posts. I also could not draw table
with invisible border. I am not sure if the problems were caused
by being hosted by WordPress or not. I looked around and
found upgrade “Custom Design”.
Can anyone tell me what does it include? According to the description,
it allows me to change CSS. I have not used CSS. Can anyone tell
me if it would allow me to resolve the two problems that I mentioned
above.

Many thanks,