What records should I keep for a homeschool business project?

More than you think you need and less than it sounds. The useful rule is that you want enough to reconstruct what happened a year later, when nobody remembers.

Five things cover it.

A time log. Rough weekly hours, split between the reading and workbook, the actual jobs, and anything else. This is what credit hours get calculated from, and reconstructing it in June from memory does not work.

The completed workbook. It is the primary evidence and it already exists, so nothing extra is required.

The money records. What came in, what went out, dates, and customers. Doubles as a math artifact and as the thing that answers the tax question if it ever comes up.

Photographs. Before and after shots of jobs, the market table, the product, the flyer. These take seconds and they carry more weight in a portfolio than any written description.

A written reflection at the end. What they set out to do, what happened, what they would change. One or two pages. This is the single most valuable document in the file, and it counts as composition as well.

Two optional additions that are worth it. Any customer who says something kind in a text is worth a screenshot. And a short list of what they can do now that they could not in week one, written by the kid, which is often more revealing than anything a parent would write.

If your state uses portfolio review, check what the reviewer actually wants, because expectations vary and some are more specific than others.

For a college-bound student, keep all of it. A business that ran for a year is strong material for an application, and the details fade fast without a record.