The particle は (pronounced wa, not ha) marks the topic of a sentence — the thing you are talking about. It tells the listener: as for X, here is what I want to say about it.

The topic is not always the grammatical subject. は simply sets the frame for the rest of the sentence. Think of it as shining a spotlight on one thing before making a comment about it.

は attaches to nouns and noun-like words. The comment that follows can be anything — a noun, verb, i-adjective, or na-adjective.

When は replaces another particle like が or を, the original particle disappears. But with location particles like に, で, or から, you add は after them: には, では, からは.