Putting documents in a ZIP file does not, by itself, make them private. Packing, reducing size and encrypting content are separate choices. 7-Zip supports encryption for both ZIP and 7z, but the format name alone does not tell you which settings someone used.
Start with the recipient
Imagine sending three forms to a colleague. A single archive makes the bundle convenient; it does not answer who can read it. Before preparing sensitive documents, ask which archive application the colleague can use. Choose a supported encryption method deliberately rather than assuming that any password box produces the same result.
Try the exchange first with an unimportant text file. Close the archive application, reopen the test archive and attempt to extract its contents. Ask the recipient to repeat that check in their actual application. An unsupported format is a compatibility problem, not evidence that the document itself is damaged.
Keep the working copy separate
- Retain your original documents until the recipient confirms receipt.
- Give the archive a neutral filename rather than putting personal details in its name.
- Arrange the password through a separately agreed channel.
- Review where extracted copies will remain after opening.
An encrypted bundle does not undo earlier sharing, protect a recipient's unlocked computer or remove files already extracted. Treat it as one particular way of delivering a copy, with a clear recipient and a clear end to the task.