Can I add notes and checklists to an event?

Yes, on every plan. Open an event you can edit and click its description. Add a hotel link, a packing checklist or a short progress note. Use the toolbar for headings, bold text, links and lists, and tick off checklist items directly in the description.

On desktop, choose Expand panel at the top for more room to write, with the date and other details beside your notes. You can add notes to Sometime items too; they stay with the item when you give it a date.