If you have a PC, you have to use Japanese IME: https://www.coscom.co.jp/learnjapanese801/install_ime.html There are other explanations elsewhere including from Microsoft. If you have a Mac, you simply go to your settings and then keyboard and add Japanese. A little icon will be on the top bar with an American flag or an あ. If you have an iPhone, you can go to settings, general and then Language/region. If you have an android, I think you have to download a keyboard. When I had one, I think I used Gogo keyboard or something. You can simply call hiragana and katakana, "kana." Let me know if you have any questions!

You mean like this? はじめまして If so, you can type like that on your smartphone or your Windows or Mac computer. There are four writing systems you should learn: -Hiragana -Katakana -Kanji and Romaji, which is the writing of Japanese using the roman alphabet. (ex: nihongo wa muzukashii desu) Usually, to allow your device to type in hiragana/katakana/kanji, you have to go into setting and the keyboard settings and add an input source or character set. I can't help more without knowing what type of system you have!