www.trading212.com/invite/11QRtcsbjl
Within 3 business days after both you and your friend have verified and funded your Trading 212 Invest / S&S ISA with the Minimum Deposit.
Note: The minimum deposit amount can vary based on the region.
The promotion requirements must be met no later than 10 days after the account's creation.
https://www.trading212.com/legal-documentation/invite-a-friend/First-Deposit_EN.pdf