A line break is simply the end of a line. If you end a line mid- clause (like I just did there), it's called enjambment. (E. E. Cummings is the mast er of this technique.) Ending a line at a natural pause (as I did there)
is called a "end break."
(The pause can be a comma, a natural feeling pause, or a period.)
write a poem with line breaks as you normally would then after chop each line in half and write it in a new way then stick multiple lines into each other so your lines are very long and see how that feels.
then add space
or less space between some lines play with line breaks
You might end up with four (or more) versions of today's poem.
(This can be done with haiku, too - do the first version as a traditional haiku, then change how many lines you have. See how different it makes the poem feel, even though the syllables stay the same.)
Start from the poem you need to write today, the poem that wants to come out. Let it come out the way it naturally would.
And then play with it, after you finish. Not editing the words, but changing the line lengths and adding in spaces to see what it does to the poem. (Just noticing. And you may feel that one version is better, but other people might have a different opinion and that's ok, too.)
Have fun experimenting with line breaks today!
Or not, no need to follow the prompt if you're not feeling up to playing with today's poem. What matters is the daily writing and the poem that is waiting inside you, to be written today.