If it's Android or Apple, there are two ways. One is to write it directly in your notebook and copy and paste it to other places when necessary. Mobile phones generally have the function of automatically synchronizing notepad files, but I suggest using evernote, which is called Evernote in Chinese and Baidu in official website. Just apply for an account on it. One of the biggest advantages of this software is multi-platform, that is, you can write a paragraph on your mobile phone, and it will be automatically saved to its server synchronously. When you log in to other devices such as a computer or tablet, the saved content will appear on your computer. For you, you can write and save at any time and continue writing on other devices at any time. The only thing you need is an internet connection.
If it is a non-intelligent machine, it will be more troublesome, because there is little software support for non-intelligent machines, and only commonly used software such as QQ is more common. If it doesn't work, you can write it in SMS or even QQ space, but uploading is very troublesome and easy to lose, so it's best to write it on smart phones and computers.
One more thing, if you use evernote, it should be noted that although evernote is in Chinese, the accounts of the two are not universal, so the text saved on Evernote will not appear in Evernote, and vice versa.