I submitted a proposal and client sent message asking for my phone number to discuss. Should I trust this? To give my phone number right away before chatting. Being overly cautious here. This is my first proposal response.
If you feel uncomfortable sending your number, you can let the client know that you would appreciate doing a video call to discuss the project further.
I would be wary with clients who ask for information such as my address, and my phone number if we don't have a relationship yet. When I was freelancing, I shared my number with my client only after I have established a relationship with him, and a contract was in place.
Since you are new, I highly recommend that you read up on the "Safety First!" section of the freelancer resources we have compiled, and these tips for avoiding questionable jobs for more information about working safely through Upwork.
Welcome to Upwork! If giving out your phone number makes you uncomfortable, there are so many other ways to conduct an interview call. Upwork has a phone option but it doesn't always work. I've done Google Hangouts (note many scammers use this option), Zoom, Skype and Blue Jeans calls with and without video.
Good luck to you!