How can i get haruka one way

I am planning to visit osaka and kyoto. Can i get haruka one way ticket only jr west website and the other part of reservation website ( Klook ) or also get in the kansai airport?. And one question can i use one way haruka from kyoto to kansai airport?

You just buy the ticket at the station. One way.

no need to get the Haruka ticket from the website, just get it when you reach the airport.
and yes, you can take Haruka Express from Kyoto to KIX. since klook has the discount, why wouldn't you get the ticket from klook both way though?

I bought the one-way discount Haruka ticket from Kyoto to KIX online from the JR website. It's only for foreigners and it saved about 1,000 JPY. You can only retrieve it at certain stations of which Kyoto Station is one and I picked it up yesterday. You have to scan your passport in the machine....