Wooden windows, drilling required, how to hide it again later?

I hope you can help me briefly. It's about the fact that I have to drill a few holes in wood. It's about my windows, which unfortunately are made of wood. I have to drill into them, one way or another, as described here. Before I do that, I want to make sure that the holes can be closed again later and concealed reasonably well. Is there something that makes the holes no longer noticeable afterwards? What do you recommend for this?

What does this have to do with Ikea??? Please contact a hardware store. Because IKEA issues are handled here. Topic changed and post closed.