Tokyo
Toukyou
proper noun
The East Capital in Japan is Tokyo. If you look on a map and compare it to 京都 (Kyoto, the other capital in history), you'll see it's East of Kyoto, making it the East Capital, Tokyo.
とうきょう
This is a jukugo word, which usually means on'yomi readings from the kanji. If you know the readings of your kanji you'll know how to read this as well.
東京えきから中川えきまででんしゃで行って、中川えきからみかん山までバスで行きます。
We will take a train from Tokyo station to Nakagawa station, and then we will take a bus from Nakagawa station to Mikan mountain.
今から東京に行かなくてはいけないので、そろそろお会けいおねがいします。
I have to go to Tokyo now, so may I have the bill, please?
東京についてすぐに、マクドナルドに行った。
As soon as I arrived in Tokyo, I went to McDonald’s.