You have been sent files through Safe Transfer. Rather than attaching them to an email, the sender put them behind a check that confirms you are the person they meant to send them to.
Opening the link shows you what is waiting without unlocking it.

What the page tells you
- Who sent it: their name and company.
- What it is: the subject they gave it.
- How many files and how large.
- When it expires: after that the link stops working.
- Who it is for: your name, as the sender entered it.
The files themselves are listed but locked. Nothing downloads until you have verified.
Why the extra step
Email attachments go wherever the email goes: forwarded, sitting in an inbox somebody else can reach, delivered to a mistyped address. Safe Transfer is for files where that matters: payroll, medical records, contracts, anything under an NDA.
The check means the sender can show afterwards that only you opened them.
What it costs you
Nothing. You need no account and no subscription, and you will never be asked to pay. The sender is charged for it.