If you’re watching only Naruto Shippuden , the closest you’ll get is Episode 500 (the wedding and lead-up), but for the actual ceremony, you’ll need to watch Boruto Episode 18.

For readers, the final chapter of the original manga shows Naruto already established in his role as the Seventh Hokage, though the ceremony itself was later detailed in a special one-shot manga. Why Isn't It in Naruto Shippuden?

If you simply want to watch Naruto acting as Hokage, you should begin watching .

To answer your question directly: