Answer 1

its the prompt when you are using the python interpretor.

basically something that tells you its ready to accept user input

Answer 2

It's called prompt, telling you that python is ready to accept instructions.

Answer 3

you dont, it just appears when you use the interperetor.

2 main ways to run .py script:
through the interpretor (uses >>> and accepts one line at a time, hence the prompt)
&
through an IDE (uses your choice of availible interpereters and runs multiple lines of code one after another automatically)

Sololearn uses an IDE, so no use for >>>