Electronic Travel Authorisation
英國
可用 App 申請或網頁申請，過程至少需要提供護照照片和個人照片。
申請完成後會收到這樣的信：
ETA reference number: xxxx-xxxx-xxxx-xxxx
Dear xxx,
Your ETA application has been approved. You can now travel to the UK.
Your ETA is valid until: xxx.
You can travel to the UK as many times as you want until your ETA expires.
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