"Do you come here often?"
Translation:Vous venez souvent ici ?
"Là" means "there" and "ici" means "here". They are interchangeable in many situations, but the question specifically asks about "here", so only one is correct. "Do you come here often" and "Do you go there often" are two different questions and utilize two different verbs (venir vs aller)
Actually, they are not really interchangeable because each belongs to a different register of speech:
- viens-tu ici souvent ? or venez-vous ici souvent ? is the most formal way of asking the question (with a verb-subject pronoun inversion)
- est-ce que tu viens/vous venez ici souvent ? belongs to the standard register of speech, that you can use in writing or in speech
- tu viens/vous venez ici souvent ? is the most informal way of asking this question, with only a question mark at the end, and your voice raising on the last syllable. It is not recommended in writing.