Have you ever wondered what happens after you click on send button? Allow me to explain the process. Once you click on send button, the transaction goes to the nearest miner. Miner validates your transaction and passes it to other miners. Other miners will do the same thing and within a couple of seconds, every miner in the Bitcoin network will have your transaction. 

After validating the Transaction, the miner adds your transaction to the waiting room. This waiting room is called Mempool. Now your transaction is waiting for its turn to get included in the next Block. 

Once your transaction is added in a Block and Block is successfully mined, Miner will remove your transaction from Memory Pool and your transaction is confirmed now. 

Miner always picks transactions will High Fee first. If your transaction fee is low, it may take some time to get included in a Block.