TxIn stands for “Transaction Input”.
In Bitcoin and other cryptocurrency transactions, it is an instruction to deposit.
The antonym for TxIn is TxOut, which stands for “Transaction Output”.
The basic structure of a Bitcoin transaction can be roughly divided into two parts: TxIn and TxOut.
The transaction record itself is not encrypted. It can be viewed by anyone who is a member of the blockchain network.
In order to use a bitcoin designated as a TxIn, a digital signature (private and public keys) by the sender is essential. These are paired, and if either one of them is missing, the digital signature is impossible.
Also, when exchanging bitcoins, the amount of TxOut must match the amount of TxIn. If they do not match, you will need to add new bitcoins.