Step: 1 => Open your Shopify admin panel.

Step: 2 => Click on the Settings button from the side menu and choose General (See the screenshot below).

Step: 3 => Now click on the Change Formatting link inside the Store currency section (See the screenshot below).

Step: 4 => Copy the following code.

HTML With Currency 

<span class=money>${{amount}} USD</span>

HTML Without Currency

<span class=money>${{amount}}</span>

Step: 5 => Paste the copied money formats in HTML with Currency and HTML Without Currency Input fields (See screenshot below).

Step: 6 => Now click on Save Settings button.