Short answer
The best way to share sensitive documents without email is to use a secure file delivery workflow that protects files before upload, grants access to the intended recipient, limits how long access lasts, and avoids creating uncontrolled attachment copies in inboxes and backups.
Why not email
Email attachments are easy to forward, hard to revoke, and often retained in multiple mailboxes. Even when mail transport is encrypted, the attachment usually becomes a readable copy for every inbox that receives it. That is not a good default for client records, employee documents, legal packets, financial exports, or identity files.
Recommended workflow
Prepare only the documents the recipient needs, remove unnecessary sensitive filenames, choose account-bound sharing when the recipient is known, use secure links only when convenience outweighs identity binding, set expiration, and review access after delivery. For high-risk documents, verify the recipient through a second channel.