I will pay an extra 20% fee because I haven't added a tax number to the ad account. I don't have a tax number, and I don't want to pay 20% extra. I don't think there's a way to get rid of this. However, it doesn't perform verification when I enter the tax number.If you mean avoiding taxes legally, you can't simply skip taxes because you don't have a tax ID. Don't use fake information or someone else's tax details.
If you mean avoiding extra taxes/fees charged by Meta, that's different some charges depend on your country, billing setup, and whether you provide a valid tax ID. Meta's official documentation has tax related requirements.