is this possible to make placemark like this?

the website is
yootheme.joomlable.com/index.php/anqing

Hi, yes.
You can enter any HTML text into "Addition HTML text" field, and format it as you want.

PS. Nice to hear that my extension is used. Therefore I will come back to its development.

hi, i have used "Addition HTML text" but don't see any effect.

Addition HTML text you can format as you want, because it is HTML. I don't remove any tags there.

When I visit your link I think I understand.
You allow insert placemarks from frond end, and in this case I don't show Addition HTML text.
For create new placemarks I can suggest not use this feature.
You can read in my docs for Google component how integrate RS Forms with my component. And insert placemarks from it into my tables. And disable change placemarks from front end, in this case this field will be displayed.
Of, if you don't need create new placemarks from front end - disable feature and enter your data from admin section

where is the docs showing how to integrate RS Forms with zh baidumap