Step 1: First, check UV on the objects
Map images on objects will be correctly exported only if you have textures coordinates on the 3D mesh

In the Material editor apply a texture in the color channel.
Don't forget to apply a material on each object with texture coordinates (UV).

Step 2:

Go to Edit>Perferences (CTRL+E)
Check "Save Animation" before exporting animated objects. Enter appropriate frame rate in "Keys/Second.

Choose "Referenced" in "textures" roll out menu

Go to "File>Export"
Choose the export type : VRML 2(*.WRL)

Step 3: In the exporter window :
Browse to your saving folder
Give a name to your Vrml file
At last, click "save" button

By default, Cinema 4D exports textures without path : url "texture.jpg"
In that case one solution to import geometries and texture in Webseed Studio 3D is to put Vrml and images files in the same folder

Another solution to solve the problem is to edit the path in Vrml file.
Open the .WRL with a text editor and find the "url" node
If Vrml is at the root and textures in a folder, the url is : url "./MapFolder/Map.jpg"

If Vrml and textures are in individual folders at the same level, the url is : url "../MapFolder/Map.jpg"

| ! | Keep in mind that realtime engines need square maps with n exp size (8, 16, 32 64, 128, 256,512...)
You can combin them, for example you can have a 128 x 512 image.
There are exceptions :
On a environment map, width and height must be equal.
The alpha map must have the same dimensions as the diffuse map (if you use one)
Vrml format can only save standard material with simple texture in color channel.
Webseed Studio 3D only supports JPEG, GIF and PNG (8 and 24 bits)