Type of data for executing transaction. When executing a transaction, additional data may be required depending on the purpose of the transaction. For example, when you call a SCORE method, you have to specify which method you want to call, arguments of the method, etc. Depending on the purpose, there are three types:
message. In the case of a simple coin transfer, the data type is omitted because there is no need for additional data.
call: used when calling a function in SCORE
deploy: used when installing or updating a SCORE
message: used when transferring a message