Iriyavahiya and Michhami Dukkadam are both important in Jain Dharma, but they are not the same.

1) Iriyavahiya

• This is a specific Pratikraman sutra / repentance prayer.
• It is recited to seek forgiveness for ahimsa-violations done unknowingly while walking, moving, or performing daily activities.
• Its focus is on faults caused to living beings in motion.
• In many traditions, it is also called Iryavahiya Sutra or Iryapathiki Pratikraman.

2) Michhami Dukkadam

• This is a general expression of apology and forgiveness.
• It means: “May my wrong actions, words, and thoughts be forgiven.”
• It is used more broadly, especially during Paryushan, Samvatsari, or whenever asking forgiveness from others.
• It is not one fixed sutra only; it is a forgiving attitude and phrase.

Simple difference

• Iriyavahiya = a formal Jain sutra for forgiveness of unintentional harm in movement and activity.
• Michhami Dukkadam = a general Jain phrase used to ask forgiveness for all faults.

In short

If you want, I can also give the meaning of Iriyavahiya sutra line by line.