Hi!
Is there any possibility to invite a user to answer a question? Like here, in Quora:
Yes, use the invite button on the topic.
You must be TL2 to send invites however.
Agree with Jeff, right now @Agnieszka_Jaskiewicz you have TL1 here on discourse.
When you get the TL2, you will see the “invite button” like:

Some off-topic points:
Regards!
Thanks! What do you mean with TL2? What are the next steps when a user gets a request to answer a question? Does he get an email or what?
Search “trust level howto”. Find Understanding user statuses, roles, and permissions
I nostri utenti ottengono TL2 di default. Vorrei mantenere l’opzione “invita a rispondere” solo per gli amministratori perché temo che gli utenti possano spammarsi a vicenda. Come possiamo abilitare questa opzione da TL3?