How do transactions happen in blockchain?

For a public blockchain, the decision to add a transaction to the chain is made by consensus . This means that the majority of “nodes” (or computers in the network) must agree that the transaction is valid. The people who own the computers in the network are incentivised to verify transactions through rewards.

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Can I spend unconfirmed transactions?

Basically yes. You can spend money one block after you receive it . There is nothing built-in to bitcoin that knows anything about the arbitrary custom of waiting for six blocks in order for a payment to be confirmed. Exchanges may not let you send unconfirmed coins, but you should be able to do it with your own wallet.

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