an adverb is a word that modifies or describes a verb, clause, sentence, or other adverb. 'Later' is an irreverent way to express that something will happen after some amount of time.
Adverbs often answer questions regarding when, where, why, or under what conditions something took place. This adverb is most commonly used informally since its purpose is to be a conversational filler or a way to add emphasis or add other wordplay.
1. I’ll send you the report later.
2. I totally forgot to turn in that homework, but I’ll do it later.
3. I’ll talk to you later, I have to run!
Though this word is an inevitable part of some English-speakers’ casual conversations, it can also be overused when making formal written or verbal statements, which can cause it to seem too casual.