@SAra **********
This is a quite universal question that comes up from time to time, and the only possible answer is that it’s embassy dependent. Some embassies allow you to get a visa on just an inbound ticket, some also demand an onward ticket within 60 days even though you also are entitled to do a 30 days local extension. So therefore it’s no other option to suggest that you call the embassy and ask and buy a changeable ticket or a cheap online onward ticket if this is the case.