Learn Spanish (Latin America): Queremos que la comunicación sea mejor este año. - We want communication to be better this year.

sea is the present subjunctive form of ser (to be). You need the subjunctive here because the first part of the sentence expresses a desire (Queremos) for something else to happen. Whenever you use verbs like querer que or esperar que to talk about a different subject (in this case, la comunicación), the second verb must be in the subjunctive.

In English we say "want communication to be". Why does Spanish use que?

In English, we use the pattern "want + noun + infinitive". Spanish does not do this when the person or thing doing the action changes. Because "we" want, but "communication" is the thing being better, you have to use a structure that literally translates to "We want that the communication be better." That "that" is que.

Why use a form of ser (sea) instead of estar (esté) here?

You use ser to describe the fundamental characteristics or qualities of a noun. Since we are describing the overall quality of communication (making it a "better" thing), ser is the right choice. estar is used for locations, emotions, or temporary states, which doesn't fit the idea of improving the general quality of something.

Why do we need the word la before comunicación?