The domain and the hosting should belong to the company that paid for the site. A domain registered in the supplier panel and a server billed to the supplier are not yours when the work ends. Knowing a password does not mean the invoice is in your name.
Whose name is on the invoice
The holder shown on the domain record should be the company. If the renewal mail goes to a personal supplier inbox, the site can drop when the term ends and you hear about it late. The server invoice follows the same rule. If the monthly charge sits on a supplier card, the site stops when that card stops. The record and the invoice carry the company name. If they do not, launch depends on a polite transfer.
A panel password is not ownership
A username sent to you does not mean you are the holder. If the real account belongs to the supplier, closing that user is one click. If DNS, mail and the backup sit in the same panel, you lose all three. The backup also sits where you can download it. If you cannot download it, it is not yours.
The ad account and the code sit with the company too
The domain and the server are not the whole list. The company should own the domain, the ad account, and the code. If ads sit under a supplier manager account, you cannot see the campaigns. If the code sits in a personal repository, you cannot open the site somewhere else. All three are written on the same day, at the start. A transfer left to the last day moves the launch date.
Open them before launch week
Accounts are not remembered on launch day. The record, the invoice, the repository and the ads property are opened in the company name in the first week. HED Creative, the partner in Berlin or Ankara, puts these four lines at the top of the scope. An account the supplier holds is access only if the company invited them. It is not ownership. The work should continue after the invite is removed.
To have the invoice name written, say on website development who receives the bill today. The list for the day you leave: code handover contract.