Susan J wrote:
If they like my sample, then I will get a contract.
Not necessarily. Plenty of clients will ask for “samples” just to get their work done for free, and have no intention of hiring anyone. “They did not send me a contract but wanted me to start work” – that’s a huge red flag, right there. A promise to hire you or pay you isn’t enforceable in any way if you weren’t properly hired first. But you’ve done a whole bunch of jobs on Upwork, so it’s surprising that you don’t understand how payments work?