What is field "type" in transaction?

When I call eth_getBlockByNumber, I get a field named “type” with value of “0x0” in transactions. But I didn’t find any descirption about this.
So what is the “type” meaning and its values mean?

hi @zengcunkai and welcome to the Infura community !
I guess you’re referring to Typed Transaction Envelope, see EIP-2718: Typed Transaction Envelope