Hi Stéphane 

Thanks for posting in the Lucidchart Community! You can add line breaks to your notes by adding
right after the point you’d like to break your text. This will allow you to create a multi-lined note. 

For more information about our sequence markup tool and the supported markups please take a look at the UML Sequence Markup article from the Lucidchart Help Center and let me know if you have any further questions!

Great thanks!

This is probably obvious but  avoid any confusion - The note above the example incorrectly shows a forward slash (i.e. /n). The example itself is correct it is a backslash (i.e.
).  

Hi Dean 

Thanks for your post and for calling our attention to that typo! You're right. I've edited my response to correct that mistake. Thanks! 

use Command+Enter or Ctrl+Enter on windows. that's work for me. 

This answer appears to be outdated. In the example markup for the sequence diagram, multiline messages and notes are created using <br/>, not \n or /n.

Hi @ChibiJosh, 

Thanks for your post! Both \n and <br/> will work to create a line break, as you can see from the screenshot below. Thanks for adding a new markup to our options!