its basically just typing in romaji too... unless you get a japanese keyboard that is not on qwerty (like in 1 key you can type な instead of typing n and a) but in my experience even japanese people rarely use that kind of keyboard too
If you're on mobile, you can also try out the 12-key flick keyboard. It's tricky in the beginning, but fun to get the hang of! You can try enabling it through your keyboard language settings. Do watch out though, because afaik it turns every setting of your keyboard into Japanese; make sure you know how to turn it back. (For me, it's when I hold the sideways square-bracket button, or the option 次の言語)
As for how it works: every key is a constant group. (E.g. "k" contains かきくけこ). Press the key for the a-ending. Hold the key and swipe left for the i-ending, up for the u-ending, right for e, and down for o. You can add " and ° after having written the kana. And with the button with kanji, you can turn what you've just written into kanji.
I used this guide to install the keyboard - tofugu guide. It has instructons for Windows and Mac and Android and Apple systems so it's pretty comprehensive. There is also some google keyboard too but I haven't tried that one.
As for actual typing "how to" tips try the How to type guide too. Lots of details and kaomoji too! ฅ^•ﻌ•^ฅ
