Hi @Astrid1 ,
Thanks for reaching out. The “charge tax on shipping rates” option is only needed if you are required to charge taxes on shipping in any location you sell to. If you are just starting out you likely will not need to do this, but I’d encourage you to do your own research into the tax laws of the countries you are selling into and to consult a tax professional if you are unsure of your own obligations.
Kind regards,
Victor | Shopify Social Care