Email is not formatted

My email comes through with the correct information, but it has none of the formatting I see when designing it.
I.e. instead of coming through with nice spacing between lines of information, like this:

line one with detailed information
line two with other detailed information
etc.

it comes through like so:

line one with detailed information line two with other detailed information etc.

The result is that it is very difficult for me to read when I receive it.

Does anyone know what is occurring or more specifically what to do to make emails come through with proper, readable formatting?

Thanks!