My Japanese is pretty basic, but I know enough to know context matters. So the speaker in this would be a customs officer, like at airport security, speaking to a passenger entering the country. I assume that would dictate a more formal address, with it being a professional on the clock and doing their job.
So how would they say:
“Welcome to Ōijima City. Identification and reason for visit, please.”
In case clear distinctions are useful. It's a man speaking, and they're not being gruff about it.
I've already checked google translate and it offered me this:
大井島市へようこそ。 訪問の身分証明書と理由をお願いします。 Ōi-jima-shi e yōkoso. Hōmon no mibun shōmei-sho to riyū o onegaishimasu.
Is this more or less what I'm going for? (for context, it's for a story, so it's not a city I'm aware of actually existing)