Needs checking: real brands rarely do it, scammers imitate it
A bit.ly link in a brand offer: what it hides
A shortened link (bit.ly, tinyurl, cutt.ly) hides where it goes. In a sponsorship offer, it often hides a fake sign-in page or a booby-trapped file.
What it looks like
The full offer details are here: https://bit.ly/campaign-offer. Let us know if the rate suits you.
Why it is a sign
You cannot see where the link goes before you click. A brand that has a website has no reason to shorten the address of a document: its address is exactly what reassures.
What a real brand does
A real brand sends a full link to its website or a shared document, whose address can be read.
What to do
Do not click. Ask for the full address, or look for the information on the brand's website by typing its address yourself.