Check what the recipient actually needs, prepare the minimum appropriate copy, and review the exported file rather than assuming a vault protects it after sending.
Ask for the required fields and channel
A request for proof of an address may not require every field on an identity document. Confirm the recipient and their process before sending anything. Do not enter private document data into an unfamiliar site merely because it claims to check or protect the file.
Work from a duplicate when preparing a copy. If redaction is appropriate, verify that the result removes the intended information rather than merely covering it with a reversible visual element. A watermark can communicate intended use, but it is not an access-control mechanism and does not stop copying.
Review the file that will leave your device
Check every page, image, filename and visible field. Where relevant, inspect metadata and look for extra embedded content. Keep an original only where you have a reason to retain it, and store that copy separately from the version prepared for sharing.
The PDF redaction tool, watermark tool and photo-metadata tool have different jobs. Read their limitations and test with a sample first.
Where NullVault belongs
An encrypted vault can hold the retained copy. Secure export creates an ordinary readable file outside that storage boundary; the recipient and transmission channel then matter. Read storing identity documents on a phone and the sharing guide before treating an exported copy as controlled.