Question

What are the two basic kinds of electronic signals?

Answer 1

Analog and digital.  Analog signal is represented as a sine wave while the digital signal with binary (0s and 1s)

Answer 2

I'm guessing that what you're really asking is:

"What are the two fundamental ways to add
information to an electronic signal ?"

Information is added to an electronic signal in either analog form
or digital form.

For a couple of decades now, we've gotten so good that we can do
both at the same time, making an electronic signal carry MORE
information that way.