What exactly are transactions?
The term "transaction" refers to the signed data package that contains a message that will be sent from an externally owned account to another account on the blockchain. Can be divided into two major categories:
Value Transfer
• A value (in Ether) is transferred between two accounts that are not owned by the same person.
Contract Execution
• A function/method call from an externally owned account to a contract account is made here. These transactions can be chained further, for example, the contract account can perform several internal transactions before calling another contract account or returning. On Ethereum, any type of transaction execution costs money - or gas.