Learn French: Où est-ce que vous faites le sondage ?

The pattern is [Question word] + est-ce que + [Subject] + [Verb]. Here, the question word is où (where). Adding est-ce que right after it is a very common and natural way to ask a question in French, letting you keep the rest of the sentence in normal subject-verb order (vous faites).

Why does où have an accent mark on the 'u'?

The accent changes the meaning! Où (with the accent) means "where". Ou (without the accent) means "or". They are pronounced exactly the same, so the accent is the only way to tell them apart in writing.

I thought verbs with vous usually end in "-ez". Why is it faites?

The verb faire (to do / to make) is irregular, meaning it doesn't follow the normal rules. Instead of ending in "-ez", the vous form is vous faites. It's one of a few common verbs you just have to memorize!

Could I use a different verb if I mean "take a survey"?

In French, you always "do" a survey (faire un sondage). Even though English speakers might say "take a survey" or "conduct a survey", French relies on the verb faire for this action.