وَإِنَّهُۥ (And indeed, it) starts with وَ, the most common Arabic word — it means "and".

We add "and" to connect this to what came before.

وَإِنَّهُۥ (And indeed, it) is an emphasis particle — it means "indeed" or "verily" and stresses what comes next.

We add "indeed" to emphasize the statement.