あなたの日本語は丁寧に書かれていますが、一般用語としてアメリカでなら、以下のような内容で明確です。
I have few questions before placing the order. I would appreciate if you could provide answers.
1. Is it possible to ship to Japan?
2. If so, could you provide estimate of shipping cost and time.
3. Would you accept a credit card that was issued in Japan?
4. As to warranty, how long it is covered?
Also could you please provide me how to obtain the warranty such as where to send back?
Regards,
あなたの名前
お礼
丁寧な回答、ありがとうございました!!!