A volunteer certificate is a recognition document, not a tax receipt. This file is one certificate body in plain text. Paste the body into Google Docs, replace the bracketed fields, and print from Docs. It is not a PDF download.
Organization name, volunteer name, date, and a signer line are in the body. Role and hours are optional lines. Delete them if you are not stating a role or hours. If you state hours, match the name and hours to your volunteer log before you print.
Do not treat volunteer time as a tax-deductible contribution by the volunteer. Do not record general volunteer hours as in-kind revenue. This is not legal, tax, or accounting advice.