My client posted a job and invited me to it.
I accepted it.
We've been corresponding for a while, I've done some work, but now I can't see how to bill for it.
Does the image below mean the client invited me, I accepted the invitation, but the client didn't accept my acceptance to form a contract? And I should message him to do so?
Unless a (an active) contract is showing in your My Jobs page, and the client's payment method is verified, please do not continue working on this project. As Jennifer has shared, if this is an hourly contract, it is recommended that you use the Upwork Desktop App to track time. If this is a fixed-price contract, the client should have funded the first milestone before it is recommended to start working on the project.
I highly recommend that you read up 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.
Please check your My Jobs page to see if contract was set up for this project.