Hello how are you,
1. what is the accounting entry for post dated cheques issued & post dated cheques received and please mention how it will appear in trail balance. Thanking you.

If you are sending out a cheque, they don't have the cash just yet, so you could wait until they cash the check before recording it. In the mean time, just indicate it with a note if you are doing your year end adjustments.

As for receiving the cheque, go cash it, and record it.