OpenStreetMap is not an advertising site, but you can add your business if it has some *VERIFIABLE* physical presence on the ground, for example a permanent sign on the street, or even a regular presence at the shop names on your website, such as a permanent sign in the window. If there is no permanent object present on the ground, it is likely to be removed by our map volunteers (and this is fine)

Here is an example of such a permanent signboard: https://www.openstreetmap.org/node/11151350259 (if I recall rightly, it's chained in place!)

You may wish to combine it with addressing tags, documented here: https://wiki.openstreetmap.org/wiki/Key:addr:*

Your business's contact details should use this schema: https://wiki.openstreetmap.org/wiki/Key:contact:*

Finally, here is a more general intro for beginner editors: https://wiki.openstreetmap.org/wiki/Beginners%27_guide

It is a good idea to make an account and begin editing yourself.