In order to register a player, clubs have to send the Premier League all the documents relating to the transfer, including the contract, the transfer agreement, permission to work in the UK (if required), international clearance if transferring from abroad as well as any transfer levy that may apply.
As the transfer deadline approaches, clubs are asked whether they are planning to complete any business so that the Premier League's Football Operations and Regulatory departments are prepared.
The office is staffed late into the night to answer any queries from clubs but generally they will conclude the deal club to club and then submit the paperwork.
Also in this series
Part 1: What is the deal sheet in transfers?
Part 3: What is the Premier League's role in the transfer process?
Part 4: What is FIFA's Transfer Matching System?
Part 5: How does the work-permit process work for transfers?
Part 6: Rules governing the third-party ownership of players
Part 7: Is a fax machine used for transfers?
Part 8: How many loans are allowed by Premier League clubs?