There are different ways to share a model.
1. Upload the .obj and .mtl file (if there is an .mtl file) to a file sharing host like mediafire.com and share the download url here on the forum.
2. Zip the .obj and .mtl file and do the same as 1.
3. Create a furniture library and add your model to it. Upload and share the .sh3f library file as 1.
Since .obj and .mtl files are plain text files there is no way to add an author name but you can include a license file and specify that you are the owner of the license. Include it in the zip file (as in 2). When you share the model mention the license under which you distribute the model.
Method 3. is the only way to attach a creator name to your model. You can set that when you create the library. A furniture library is specifically for Sweet Home 3D. You need the
Furniture Library Editor to create the library.
If there is no .mtl file this is because there are no materials defined for your model. This is easy to fix: when you have your pond model imported in Sweet Home 3D assign a material to the model ("Modify furniture"). It is most likely just a single material. When you export the model the .mtl file is created along with a new .obj file.
Read
this Tip&Trick post for adding water to your pond.
You can export pond+water together to get a single model.
