No, Wishpicks doesn't sell, ship or deliver anything: you buy the gift in the shop and arrange delivery there, to an address the list's owner gives you.

Shipping costs, delivery times and where it ships from are down to the shop. To get from the wish to the shop, see "Can I buy a gift on Wishpicks?".

Ask the owner directly, in whatever chat you already use. Before you do, look for a hint in the list's description and under "Note for gifters." on the wish, in case they've already said how they'd like gifts sent. The message you can leave when you reserve only goes one way, so it won't get you an address.

No: wishes, lists and profiles have no address field, so send your address in a private message, only to the person who's buying. To let people know they should ask:

For a single wish, tap Add a note for gifters in the wish, or fill in Notes for the gifters when you edit it.

Only if you type it where people can read it: your list or your profile. Everyone who can open the list reads its description and every wish's note. On a list set to Anyone with the link or Everyone, that's anyone with the link, or anyone who finds the list on your profile. So keep your home or work address, postcode and phone number out of the description, every wish's note and description, and your profile bio, which is public. More in "What can people I share my list with see?".

No, Country / Region in Settings → Profile isn't an address. Its hint reads "Affects which stores and prices you see." To change it, see "How do I change my language or country?".

The shop you bought from: Wishpicks can't change, return or refund an order. Got a gift you'd like to swap? The person who bought it has the order, so they'd sort it out with the shop.