Can we start working for the client after h1b transfer fee check is cleared

My employer filed a petition to transfer my visa on march 28th in regular basis and the check got cleared on April 10th. How long it may take to get a receipt number?

Is it good to join the client before getting the receipt number

Any suggestions are helpfull

Thanks

Shravan

The best case scenario is that you start working for the new employer after you receive the Receipt Notice. You may also consider employment with the new company under the above circumstances if it is essential to do so before receiving the receipt notice.