Confirm there are not already settings or features that do what the shop is asking for:

I have checked and there is currently no option to delete or remove a tax code from the dropdown menu once it has been created, regardless of whether it contains a typo or was added by mistake.

What does the shop want the product to do:

The shop wants to have an option to remove the tax code from the dropdown menu of the tax code section.

Why/how would it improve sales or efficiency:

Allowing shops to remove invalid or incorrect tax codes prevents accidental selection during product setup (e.g., mistyping PCO40107 instead of PC040107). This eliminates tax miscalculations on products, reduces manual error cleanup, and speeds up product creation.