Fences can be painted or stained depending of the wood being used. If the fence is made of pine it will need to be painted since they not porous surfaces.
If the fence is made of cedar or redwood there are two stain options: solid or semi-transparent. Solid stain will penetrate the wood and provide a finished look of paint. Here is a link for solid stain:
The majority of exterior paint products for specific surfaces have been addressed in this blog. Please do not hesitate to contact me regarding the different products for specific surfaces.