Save a date function

Hello, I saw at another tracking tool the possibility to save a date in my tracking graph when I change something or when I send a Mailing to my user or or or. Just to let me know why is there a peak in my graph and what’s the reason. Is it possible to implement something like that into piwik?

Do you mean “Annotate the graph with information” Annotating your data - Analytics Platform - Matomo