1. Download Adobe Acrobat (they always have free trials running - Google one)
   1. Do not use a free online tool. You’re uploading sensitive data and you don’t know how they keep your data safe.
2. Redact using the document reader
3. Print the redacted document
4. Scan and send it back

Are you overdoing it? Maybe. Will they be able to see anything or unredact the document anyway? Absolutely not.