The easiest way to ask
In conversation, this is the most common way to ask a yes/no question: you say a perfectly normal statement and raise your voice at the end. No word is added and nothing changes order.
Same words, different melody
Tu parles français.
You speak French. (voice falls)
Tu parles français ?
Do you speak French? (voice rises ↗)
Elle aime le café.
She likes coffee. (voice falls)
Elle aime le café ?
Does she like coffee? (voice rises ↗)
Typical questions
Tu viens demain ?
Are you coming tomorrow?
Il travaille ici ?
Does he work here?
Vous êtes français ?
Are you French?
C’est ton frère ?
Is that your brother?