In case I need to surrender my plate temporarily, can I do it?
Yes, you can. There's more info about this in the section " special procedures to surrender plates for a season - temporary surrender of plates"
How should I mail my plate so I can get the FS-6 T receipt?
You should send the plate via registered or certified mail and request a return receipt, that way you can be notified by the US Postal Service that we received the plate.