ᐅ Wood windows, necessary drill holes—how to conceal them afterward?

I hope you can help me briefly. I need to drill a few holes in wood. It concerns my windows, which unfortunately are made of wood. I have to drill into them, as described here. Before I do that, I want to make sure that the holes can be filled and reasonably well concealed afterward. Is there something that can make the holes hardly noticeable? What would you recommend for this?

What does this have to do with IKEA???

Please contact a hardware store. IKEA-related issues are handled there.

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