You sure can!
Creatives are allowed to “mock-up” their logo designs by showing them in a real-life application. Many people make their own templates or use some popular Photoshop templates to display their logo designs.
Here are the rules:
1) Entries in logo projects may be presented on “collateral” materials as a way of displaying how they would look. (Think signage or window displays.)
2) The creative may not imply or explicitly offer extra work outside of the scope of the project in their entry or comments.
3) Clients may not request additional work outside the scope of their projects as long as the project remains unawarded. If they wish to request additional work, clients can negotiate a new award price or an additional offer.
4) Don’t flood a project by posting the same logo on many different templates. Just don’t. You can always submit versions showing use on different templates.
5) Make sure the template you choose fits with the buyer’s project.
We hope this will help you win more projects and interact even more professionally with your awesome clients!