i have a current channel of hyperledger fabric with chaincode that does CRUD operations my question is that is there any way to make a method in a chaincode that registers the new user when certain condition match.
You can use one of several methods to get the identity of the user:
GetCreatorGetIdGetMSPIdThey are part of the Client Identity Chaincode Library, documented here: https://pkg.go.dev/github.com/hyperledger/fabric-chaincode-go/pkg/cid#section-readme
The Hyperledger Fabric docs provide some help for access control also if you're interested in that: https://hyperledger-fabric.readthedocs.io/en/latest/private-data/private-data.html?highlight=getmspid#private-data-sharing-patterns