Learn French: Je sais qu'il est connecté, où qu'il voyage. - I know that he is connected, wherever he travels.

The phrase où que (meaning "wherever") always requires the subjunctive mood. It is a conjunction of concession, meaning it expresses "no matter where" or "regardless of where," setting up a hypothetical situation that doesn't change the main fact (that he is connected).

The verb voyage looks exactly like the normal present tense. How do we know it is subjunctive?

For regular -er verbs like voyager, the present subjunctive endings for je, tu, il/elle/on, and ils/elles are completely identical to the present indicative. We know it is subjunctive here entirely because the grammatical rule for où que demands it.

Could I use partout où instead of où que to mean "wherever" in this sentence?

Yes, but the grammar would change. Partout où also translates to "wherever" (literally "everywhere where"), but it is followed by the indicative, not the subjunctive. While partout où il voyage focuses on the actual physical places he goes, où qu'il voyage adds that concessive nuance of "no matter where he might travel."

Why does connecté end in an é instead of er or ée?