Not entirely true. There are bits in binary files that cannot be rendered correctly by text editors. In fact, if a text editor cannot read a bit, it might omit it or substitute it with a generic placeholder. Instead, what you would do is encode the file into a text format and the transmit it to somebody, who would then decode the text back into its original file format.

This is how email attachments and uploading/downloading files from the web work. Usually that text format is called base64. In email attachments, they go one step further and typically limit the encoded data to fixed length lines called chunks.

But yeah, sending raw binary data as text requires special formatting first. Opening it up in a text editor and copying and pasting is not enough.