Or just copy/paste into a google translate window set to Japanese, and read the text below the input box. Not 100% accurate but usually pretty close unless the title is a pun. Just make sure the language is set to Japanese or you may get the Chinese reading of full kanji titles which is VERY different.
You can look it up in a Japanese dictionary. If you’re using iOS devices, you can download one.
If you want to input a kannji,you can using a Chinese handwriting input.
If you are talking about the kanji name in the animes maybe the only way is to listen it in the animation or refer from their HP.
Learn to read kanji, and you'd know how that word should look like in hiragana - Then you can convert it into romaji.
Of course, in practice this isn't always straightforward, because a kanji depending on the context could be read differently, especially if it's from old texts (or when someone is imitating old Japanese).
Well learning Kanji would sure the most impressive way, but if you need fast results you can try sites like https://j-talk.com/convert to convert and translate.
Doesn't always help. Depending on the context, the hiragana/romaji for a kanji is different. Sometimes it's due to historic reasons, sometimes you get that when you put two kanji together and it becomes one word.
Basic translators will help with very basic things, but when you go deeper into names it gets convoluted. If you want to go deeper, learn Jap. Just remember that transliterating generally doesn't work.
The best method is to: Read aloud in Japanese while maintaining original pronunciation. Then write down what you just said, this time in English.