It’s Markdown syntax. Single newlines are ignored so the text can be styled to be 80 characters wide for example but still have it rendered with another line length while two newlines result in a new paragraph. It’s not about “space efficiency”.

To get a visible linebreak without creating a paragraph, add two spaces at the end of the line you want to break.

hello↵
↵
this is the first line␣␣↵
this is the second line↵
↵
more text here

… results in this:

hello

this is the first line
this is the second line

more text here

(Actual rendering depends on your renderer.)

Here's a formatting guide that should help. I always used bullet points for multi-line items.

You can put a backslash before the newline, like this

line1\
line2\
line3

gets formatted as:

line1
line2
line3

Two
spaces
before
you
press
enter.

It's a Markdown thing. End the line with two spaces.

First line (two spaces) ->
Second line

Two spaces at the end of the line
Will give you what you're looking for

• Markdown also supports
• Using asterisks followed by a space at the beginning of the line
• To create bullet points like this

1. Or numbered lists
2. Like this one
3. Which is pretty much just what-you-see-is-what-you-get

Thanks for the question. I've been wondering how to do this myself.

Two spaces after the last character.
Like
This
On my phone I have to wait about a second between each space I enter because Android wants to automatically add a "." to the end of a sentence if I double space too fast.