Should a person who missed the congregational prayer in the mosque make the Adhan when praying alone, or should they only perform the Salah?

The Adhan is a Sunnah for every obligatory prayer, and the Iqamah is more emphasized than it. Whoever enters a mosque where prayer has already been performed may choose to make the Adhan and Iqamah, or pray without Adhan or Iqamah; this is because the Adhan and Iqamah of those who prayed before him suffice for him. If he does make the Adhan, it is recommended that he do so quietly and not audibly.