The structure of block in Hyperledger Fabric is very similar to that of bitcoin. The hash(H) is
computed as follows:
H(H) = hash([transactions] || H(N-1) || N)
The block looks something like this:
message Block {
    BlockHeader header = 1;
    BlockData data = 2;
    BlockMetadata metadata = 3;
}
and the definition of Blockheader is:
message BlockHeader {
    uint64 number = 1; // The position in the blockchain
    bytes previous_hash = 2; // The hash of the previous block header
    bytes data_hash = 3; // The hash of the BlockData, by MerkleTree
}
Check out https://github.com/hyperledger/fabric/blob/master/protos/common/common.proto to know more.