NotePlan 3 3.7.1 for Mac was available to download from the developer's website when we last checked. We cannot confirm if there is a free download of this app available. The software lies within Productivity Tools, more precisely Office Tools. Please check the Mac app with an antivirus before launch as it is downloaded from the developer's website, and we cannot ensure that it is safe. This free Mac app is an intellectual property of NotePlan S.A.
From the developer:
NotePlan 3 lets you manage tasks, notes, and calendar in one place. The tool is suitable for project managers, designers, researchers, writers, students, or anyone who wants to be organized and efficient. You can create tasks and notes quickly with Markdown, add #tags to organize tasks and notes, use @mentions to find people, reschedule to-do items easily, create flexible recurring tasks, create your own network of notes, and much more.
You may want to check out more software for Mac, such as NotePlan, which might be related to NotePlan 3.