To be able to add Business Map icon, first make sure that you have added the address of your business. This can be done under the address section of the company information form, in the website settings page.
The next step is to is to add a Map item in your contact page, with the location that you want the Map to point to (e.g. your business address).
If you have added your business address in website settings correctly and you have added the Map item to your contact page then the Map icon will automatically appear on the mobile site.
To learn more about adding the business address in website settings click here.
To learn more about website settings click here.