In ethers a Signer is an abstraction of an ethereum account, which can be used to sign transactions and send signed transactions to the Ethereum Network to execute state changing operations.
The available operations depend largely on the sub-class used.
The most common Signers are:
Wallet, which is a class which knows a crypto-wallet private key and can execute any operations with itJsonRpcSigner, which is connected to aJsonRpcProvider(or sub-class) and is acquired usinggetSigner()