You can use any one, but typically people use " " for everything. I like using ' ' for single characters and " " for everything else.
Those two aren’t even the only ones that exist, you can also use these if you want:
print('hi')
print("hi")
print([[hi]])
print([=[hi]=])
The last one can have as many equal signs as you want, so you can technically do this if you felt like it 
:
print(proof [============[ LOL ]============] proof)