Everyone can add annotations (marks) inside Google Maps and embed the map as they like.
Here is how to do it. Make sure that you are logged inside your Google account. Search on Google for “google maps”, enter on the first result.
Search for an address where you wish to place the annotation. On the spot you want to place the annotation, right click and click on “what’s here?”.
Click on “save to map” from the left side of the interface, “create a new map” and save.
Click on “edit”, notice that some marks will appear on the top of the map, click on the mark and drag it on the spot you wish to place it.
Enter the title and a description, do the same thing on the left panel, click on “save” and then on “done”.
If you have any annotation that you don’t want, just click on it from the left panel, then click on “edit”, and delete it.
To embed your map including the annotation (mark), click on the “link” icon (embed), “Customize and preview embedded map”, from the next pop-up that will open, drag the map until you get a perfect positioning (notice that the code will auto-change below the map as you drag and move), copy the HTML code and paste it inside your webpage.
Some places like non-urban zones will display something different on the left panel, if you click on “Add a place to the map” and you get this error, “We do not support adding a place here yet.”, just try to use the method explained here, doing “right click” and click on the “what’s here?” link.