I need an info on how to scan a document form my iphone 8

You can use the scan feature in Notes or you can download a standalone scanning app from the App Store.

Scan a document in Notes

With iOS 11 and later, you can scan documents in Notes. You can also add a signature or manually sign a document. With an iPad Pro or iPad (6th generation), you can add a signature or sign a document with your Apple Pencil.

To scan a document:

1. Open a note or create a new note.
2. Tap , then tap Scan Documents.
3. Place your document in view of the camera on your device.
4. If your device is in Auto mode, your document will be automatically scanned. If you need to manually capture a scan, tap  or one of the Volume buttons.
5. Drag the corners to adjust the scan to fit the page, then tap Keep Scan.
6. You can add additional scans to the document or tap Save when you're done.

To sign a document:

1. Tap the document in the note.
2. Tap , then tap Markup.
3. To add your signature, tap , then tap . To manually sign your document, select a tool to use, then sign with your finger or Apple Pencil if you're using an iPad Pro or iPad (6th generation).

Notes information copied from: https://support.apple.com/en-us/HT205773

-AJ