کردم

In a sentence

• من تکالیفم را انجام کردم.

  I did my homework.

  Here, 'کردم' is a form of the verb 'کردن' (to do), used in the past tense indicating an action I performed.

• او به من کمک کرد و من واقعاً قدردانم.

  He helped me, and I am truly grateful.

  In 'کرد', a related form is used to describe the action of helping. The addition of 'م' at the end in 'کردم' means 'I' performed the action.

• کارهای فردا را برنامه‌ریزی کردم.

  I planned tomorrow’s tasks.

  Here, 'کردم' describes the organizing act ('کردن') finalized for my tasks in the first-person past tense.