— Visit google map
— Type in any street address or geographic location and click the Search button.
— Select Share from Menu on left side and a popup will appear, as illustrated below.
— Select the Embed tab.
— Copy the code from the box. The code will begin with <iframe.
— In your WordPress.com homepage, go to Posts → Add or Pages → Add (or open an existing post/page in editing mode). Open the HTML Editor (Tab ‘Text’ on the right side) and paste the code directly into your post or page.
— Click Save Draft, Update, or Publish depending on the status of your post or page. If you refresh the page, you will notice that the code has changed. WordPress has converted the HTML code into the working shortcode.
Thanks to: https://en.support.wordpress.com/google-maps/