Learn Italian: Voglio sapere quando è l'incontro con Anna. - I want to know when the meeting with Anna is.

In English, we change the word order for indirect questions (from "When is the meeting?" to "...when the meeting is"). Italian keeps it simple! The word order in an indirect question stays exactly the same as the direct question. So, the direct question Quando è l'incontro? just gets plugged straight into the sentence.

Why do we use "sapere" here instead of "conoscere"?

Sapere is used for knowing facts, information, or answers to questions. Conoscere is for being familiar with people, places, or concepts. Whenever you introduce an indirect question using question words like quando, chi, cosa, or se, you must always use sapere.

Since this is an indirect clause, do I need to use the subjunctive mood instead of "è"?

No, you stick with the indicative mood here. While Italian loves the subjunctive for expressing doubt, opinions, or emotions, verbs expressing a desire to know a factual answer (like voglio sapere or chiedo) generally just take the normal indicative mood.

Is "incontro" the best word to use for any type of meeting?