Import lives in Notes → Import (for writing) and the board views (for tables). Everything imports into the workspace you are in when you do it.
Obsidian
Zip your vault, drop it in, done. The detector recognises a vault by its
.obsidian/ folder, the entire folder tree survives as real folders, wikilinks
keep working, and importing the same vault twice merges instead of
duplicating, so you can bring a vault over in stages.
Notion
Export from Notion as Markdown & CSV, then import the zip. Notion's export mangles names with hex suffixes and flattens databases into CSVs; the importer strips the suffixes, rebuilds the page hierarchy as folders, and brings database rows in as structured content.
Plain markdown
A single .md file or a folder of them. Front matter is preserved where it
maps, and the folder structure comes with it.
Excalidraw
.excalidraw scene files import as whiteboards, editable like any canvas you
drew here.
CSV
A CSV imports as a board: one row per card, with a column-mapping step so your headers land on the right fields.
What happens after an import
Imported content is indexed like anything you write, so the Mind starts reading it, entities emerge from it, and it becomes searchable by meaning. A big import is the one case where the review queue in Organize fills up quickly; collapse-all and use the group accepts.
If you are on the free tier, an import that would blow past a plan limit tells you before it starts writing, and nothing is silently dropped.
Getting back out
The exits are documented in Your data: markdown for notes (wikilinks intact), CSV for boards, PNG for whiteboards. Import is not a one-way door.