Formal:
* J'ai marché: This is the most common and general translation, meaning "I walked."
* Je suis allé(e) marcher: This translates to "I went for a walk."
Informal:
* J'ai marché: This is also used informally, but can sound a bit more direct than "Je suis allé(e) marcher."
* J'ai fait un tour: This means "I took a walk" and is a more casual expression.
Past Tense:
* J'ai marché: This is the past tense, meaning "I walked" in the past.
Present Tense:
* Je marche: This is the present tense, meaning "I am walking" or "I walk" (general action).
The best choice for you will depend on the context and the level of formality you want to use.