Apple's mobile phone synced the sogou input method from iTunes to the mobile phone, but why can't I type it when I send a message?

Settings-General-Keyboard-Keyboard-Add a new keyboard-and you will have the Sogou Pinyin input method downloaded. When sending a text message, click on the earth icon and you will see the Sogou Pinyin input method. If you don't enter the Sogou Pinyin Input Method in cy dia- click Search-you can download and install it, provided that you add 178 source code. If you don't understand, you can ask me.