While technically a question, "what's up" has become a common greeting among American youth and African Americans. The greeting is often reduced to "tsup!"

I am not sure exactly what the asker means by طرق و إجابات, but I hope this helps.

Alaa

Unless properly contexualized, there is no way to tell what this question means, and therefore, there is no way to make a serious translation suggestion.

For one thing, the verb حدث can be translated as:

happen, occur, take place, transpire, come to pass, etc.

The second considertion is the tense of the verb, which is related, among other things, to the grammatical mood (whether it is subjunctive or not).

The verb يحدث is referred to in Arabic as فعل مضارع which is used for both the present and the future, or, as grammarians like to say, الحال أو الاسـتقبال

Considering the variety of present tenses in English, the question could theoretically mean:

What happens, what is happening, what will happen, what would happen, etc.

Multiply this by all the above suggested synonyms of "happen."

If the intended tense is the present continuous, then in addition to "what is happening" and all the other synonyms suggested above, you can also have "What is going on?" Considering that the verb "to go on" means "to continue," it is naturally appropriate for the continuous tense.

But in the end, what really matters is the intended meaning, which has not been stated at all.