Okay, now that THAT is out there.. Among the rules to working safetly on Upwork (UW) is not to communicate with clients who try to get you off the platform before giving you a contract on UW. The contract is not just them saying 'you are hired' but they inititate an offer on UW and it is sent to you, you see it on your notifications, see terms and then get to accept it. Once you do that it displays on you 'my jobs' page as an active contract - and then you begin work as well as feeling free to communicate with your client on any interface - because they already made the commitment to you.
Any client that - puts their contact info on a job post,asks for money, for you to buy things, for you to click things online, for you to do shady things, - is probably a scam.
There are also jobs that are not allowed by the ToS as well as rules to follow. So, make sure you read the ToS early on to better understand how things like 'payment protection' actually works.
