What does Funds Availability Date: Jan 20, 21 mean?

[Scourge]

This message appeared after transferring money to a friend and we both don't know what it means, it transferred soon after but we are still unsure. Can anyone help out?

[kernowlass]

@Scourge 

You must have sent it using the goods/services option instead of the family/friends option?

So paypal saw them as sellers and applied the new seller hold as per link.

https://www.paypal.com/uk/smarthelp/article/why-is-my-payment-on-hold-or-unavailable-faq1987

If you mark the transaction as processed then the sender may have the option on their account in about 48 hours to mark the transaction as delivery/satisfied. If the sender confirms this by clicking on the "Confirm Receipt" button, the funds may be released to you sooner. This is not always guaranteed. 
If not then sadly its 21 days.