If you're talking about an experience in the past that is finished:
* J'ai eu: This is the most common and general way to say "I have had" in the past.
* J'avais: This translates to "I had," meaning you possessed something in the past.
If you're talking about something you've recently consumed:
* J'ai mangé: This translates to "I have eaten," and is used for food and drink.
* J'ai bu: This translates to "I have drunk," and is used for beverages.
Examples:
* J'ai eu un chien. (I have had a dog.)
* J'ai eu une bonne journée. (I have had a good day.)
* J'avais un stylo. (I had a pen.)
* J'ai mangé un sandwich. (I have eaten a sandwich.)
* J'ai bu un café. (I have drunk a coffee.)
It's important to consider the context and use the appropriate verb tense to express the correct meaning.