A transaction is unconfirmed as soon as it's created and relayed. This means that it is currently in the mempool (which is kind of a 'pool' of transactions) and has not been included in any block. As soon as a miner includes it into a block, it will have 1 confirmation. For every successive block it will gain another confirmation. So in your example, 24 is the number of blocks that have passed since the inclusion of the transactions into a block (including this block itself).
can i confirm any transaction??
Miners do that. All you have to do it pay the appropriate TX fee.