On iOS, tap the activity button and tap Encrypt. Encrypt items with the Item > Encrypt menu item or optional toolbar button on Mac.

Individual items can now be encrypted with a password, and temporarily viewed with the password, Face ID or Touch ID (including on MacBook Pro with Touch Bar). It’s completely fine to open Markdown files in a dedicated editor should you need more than Keep it offers, and similarly if you want a live-updating preview, I would recommend Marked 2 by Brett Terpstra. Keep It’s aim is to present Markdown files as something more than just plain text, and provide the fundamentals. Any CSS stylesheet will work for the preview. Keep It uses the same syntax highlighting engine as MacDown, so any editor style that can be used with MacDown can be used with Keep It on both platforms, and creating custom styles is pretty straightforward. This includes syntax highlighting, editing assistance for things such as headings, emphasis, links, images and lists and a choice of styles for both editor and preview. Keep It now has a dedicated Markdown editor on both Mac and iOS. This is the biggest Keep It update so far, particularly for the Mac, and the focus is on making Keep It a great place to edit and view notes, documents, images, video clips and more. On Mac, Keep It can now open anything in a window, show margins for any editable text document opened in its own window, and navigate the history of viewed items. Starting with this version Keep It can now encrypt items, has dedicated Markdown editors with syntax highlighting and preview, can show word counts for notes and other editable text documents, and copy clickable links to lists. Keep It 1.4 is available today for Mac, iPad and iPhone.

Tab in macdown