In order to see if the transaction has confirmed, you can search for it in any indexed transaction database. This can include Bitcoin Core running in -txindex mode, or a block explorer such as live.blockcypher.com or blockchain.info, for example. As soon as the transaction has been included in a block, it has 1 confirmation. If it is not found, or is still in the mempool, then it has either not propagated (failed validation checks), or has yet to be mined.