Do you mean "I am watching anime"? Then アニメを見ています(anime o mite imasu). If you want it to be more informal (like to your friends), you could say アニメを見ている (anime o miteiru), アニメを見てる (anime o miteru), or アニメを見ているよ (anime o mite iruyo) (sentence order→informal to really informal. All of them are friendly though)

アニメを見ています anime o miteimasu