Dollar is used in trading between two different countries. Billions of dollars are being transacted all over the world. And this transaction is just by sending an amount as a number from one bank to another bank. Where no one actually sees the paper dollar. The transaction is being completed through digital dollar...
No dude, there is no paper note printed against all digital dollar in bank. Most of total dollar in use in world are digital number created by banking system, which is managed through cooperative banking system and Federal Reserve economic activities.
When we deposit $1,000 in bank, that bank does not keep entire amount in vault. According to law, it keep small portion in reserve and lends remaining dollar to someone else. Suppose bank has given loan of $900, bank will digitally write the amount of $900 to borrower's account. As a result, the deposit amount on computer screen will be $1,900, the original note was only $1,000. In this way, commercial bank create digital dollar by giving loan.
Also, when central bank want to increase money supply in economy, they do not go to press and print new notes. They buy government bonds from commercial bank and with few clicks on computer, they credit or add billion of digital dollar to accounts of commercial bank.
You could read this:
Money creation in the modern economy 
