What do you want to be doing in twenty years?

Please don't write "wanna."  "Wanna" is how we say "want to."  It's commonly used in lyric videos and texting, but educated people write "want to."  Always follow "want to" with a base verb. (No ING)

Language Guide Men's Clothing 

Practice verbs similar to want because they stay in simple present even right now

What do you want your life to look like when you get old?