An invoice exists on every order — the buyer opens it from the order and prints it. You do not have to produce one by hand. How to get an invoice for an order
What it shows about tax depends on what you have set.
If you are registered for GST
Put your GSTIN on your store, and set the GST rate and HSN code on your listings.
Prices here include GST, so the tax is worked out from inside the price rather than added at the end — which is why the rate on the listing matters: it decides how the figure is split on the invoice rather than how much the buyer pays. Do the prices include tax?
If you are not registered
Then you are not charging GST on your sales, and the invoice says what it should: a sale from a seller who is not GST-registered. Nothing to set, and nothing missing.
Being on the ECO enrolment route is a legitimate, complete answer here — not a gap to apologise for. Do I need to charge GST on what I sell?
If a buyer asks for a GST invoice and you cannot give one
Say so plainly and early. A business buyer wanting input credit needs a registered supplier, and finding out after they have paid is a cancellation.
Worth putting in your store FAQ if you are asked regularly. Your store page
What is not this
Metzee's invoice for its own fees is a different document going the other way — Metzee to you, for the commission. Where is my invoice for Metzee's fees?
TCS and TDS are deductions the marketplace makes, not something on your invoice to a buyer. Why was tax deducted from my payout?
Three different documents, and conflating them is the usual confusion.
Getting the rate right
The rate depends on what you sell, and it is not something this page can tell you. Your accountant can, once, for your category — and then it is a field you fill in.
What you should not do is guess, because a wrong rate on an inclusive price means the split is wrong in your own records. Can I get a yearly summary for my accountant?
More: do I need to charge GST, updating your GST or business details, do the prices include tax.