Four things, in different places, and two of them stop money.
The ones that stop money
Your PAN. Required to receive payouts, and it decides the rate at which marketplace tax is deducted — without it, deduction is at a higher rate, which is real money lost for nothing. Seller settings, under business and tax. Why was tax deducted from my payout?
Your bank account. Payouts go to an account in your own name. A name that does not match is rejected by the bank, and the payout shows as failed rather than lost. Payout failed
Do not change the bank account while a payout is on its way to the old one. Settle what is in flight first. Changing your payout bank account
The one that stops selling
Your tax identity — your GSTIN, or your ECO enrolment number if you are not GST-registered. Without one you can build a store and not sell. Do I need to charge GST on what I sell?
The one that is cosmetic
Your store name and details. Change them whenever. Store names are not held exclusively, so nothing is reserved and nothing is blocked. Is my store name already taken?
Your username is the one that is painful to change later, because it is the address people have saved.
If you newly register for GST
Add the GSTIN, and then set the GST rate and HSN code on your listings — prices include tax here, so the rate decides how the figure is split rather than what the buyer pays. Giving a buyer a GST invoice
Worth doing in bulk rather than item by item, through the spreadsheet import. Listing a lot of items quickly
If your business changes hands or form
The store should be in the name of whoever the business actually is — the bank account, the PAN and the tax identity all have to belong to the owner. If that person changes, that is a conversation with Metzee rather than a field to edit. Can I sell on behalf of somebody else?
What to check once a year
The PAN marker on your Finance screen. If it says the higher rate, the PAN is missing or wrong, and you have been paying for it since the last time you looked.
Two minutes, and it is the single most profitable check on this page. Can I get a yearly summary for my accountant?
More: setting up payouts, what documents are needed, do I need a company to sell.