How do I compose a tweet to someone I am following? I have this problem on both the4 native Twitter app and Twitterific.
Find a tweet from the person in your timeline. Swipe up or down until VO says "from: screen name (username)". Double tap to open that person's info. At the bottom of the screen are some buttons, one of which is "mention". Double tap this to compose a new tweet with the person's handel already filled in.
What if I just want to compose a tweet to a a person? Meaning, I know their twitter name. They have never tweeted me.
To mention someone, which sounds like what you want to do, just type an "at" sign followed immediately by the Twitter name of the person. That's all Twitterrific is doing for you when you do what I said to in my previous comment. If this isn't what you're talking about, let me know.