Excel Invoice Formatting Help

I have an existing invoice laid out in Excel, but the formatting looks inconsistent and unpolished. I’d like you to tidy everything up so the document prints cleanly on A4, the fonts and cell styles are unified, and formulas (totals, tax, balance-due) are locked in and easy for anyone to edit without breaking the layout.

Here’s what matters most:
• Professional, consistent styling—logo, headings, body text, borders, and shading all aligned to a single theme.
• Clear, protected input fields for quantities, unit price, tax rate, and discounts, with automatic calculations running behind the scenes.
• Page setup that centres the invoice, shows gridlines only where needed, and keeps it to one printed page.
• Compatibility with the latest desktop version of Excel (I’m on Microsoft 365).

Please deliver the finished .xlsx file along with a brief note on any workbook protection or named ranges you apply, so I can update it later if required.