^^ She doesn't have to explicitly ask him out per se.
But if she consistently initiates texting/messaging/calling with him here and there, then most likely she admires him.
Women receive a lot messages from men, yes even from single male friends/acquaintances (who usually subtly test the waters), so they usually don't have the need to initiate any connection with guys. They don't even usually initiate texting/messaging with male friends even (for no apparent reason), unless this friend is like super best friend brother-like forever...but this is rare.
So it's very rare for women to pull out the phone from their pocket/purse, to scroll down the contact list, to tap his name and send them a message/text just for the sake of saying hello to him (and there's no sort of situational favor to ask from him). His name won't even cross her mind if she's not interested in him at all.
This minor effort women rarely do with random male friend/acquaintance, unless they LIKE the guy. The frequency of her doing so is a very strong sign, and usually it doesn't stop at that only.