For the first few years of homeschooling, there isn’t necessarily much physical work in terms of written work, but remember that they are still building up those fine motor skills and the muscles required to do those things. A “little bit” of copywork at a time is all of the writing they can usually handle, and it builds up over time.
Painting, drawing, tracing things in sand, cutting and gluing things, sorting things into drawers, cubbies, or muffin tins are all helpful activities for not just fine motor skills, but math, science, language arts, etc. For example, you wouldn’t expect a written narration from a 7-year old until they can write well enough, but you don’t just have to rely on oral narrations. They can draw something for narration.
If you are concerned about having enough to show a portfolio reviewer at the end of the school year (if that’s what you need in your state), save those works of art and label them as “science” or “history narration” or whatever would apply. Also, if your child is sorting buttons into a muffin tin to show different ways to show the number 5 (2 buttons + 3 buttons, 4 buttons + 1 button, etc.), then take a picture of it. Tracing letters in sand on a baking sheet? Take a picture of it.
I have kept book lists and activity lists for years to include in a portfolio of samples of the year’s work. And remember, you are probably keeping just a few quality samples for each subject that demonstrate your child’s progress over the year. You’ll be surprised at how much “evidence” of academic progress you accumulate each year.