CryptPad is an open-source collaboration suite with text documents, spreadsheets, presentations, forms, kanban boards and diagrams. The project describes browser-side encryption of document content. Team drives and sharing tools help organize collaborative work.
You can use a public instance, choose a supported hosted deployment or operate your own installation. Storage limits and support depend on that choice. Review sharing links, account recovery and the host’s terms; encryption is not a substitute for managing access.
Sources: Applications · Hosting options