How a transaction validity is verified in blockchain

Question

I understand that blockchain records all the transactions. But, what if somebody just enter any arbitrary amount to send to an address, however the account doesn't have required number of bitcoins to be sent. Say, the address has 2 btc and the user creates a transaction of 20 btc. What would happen of a transaction in such case.

Answer 1

Blockchain has the records the of all transactions that has ever happened since its genesis. Bitcoin blockchain don't maintain the balance of transactions, rather it maintains the UTXOs account. An address has the ability to spend transaction which were sent to it.

A user of the particular address cannot just enter any arbitrary amount to send. The UTXOs is the proof that an address hasthe specific number of bitcoin against the adress, and if the user tries to send more than what he has in the address, then such a txn would be considered invalid by the network.