Formal:
* Please find the requested documents enclosed with this email.
* The enclosed brochure provides further information about our services.
* We have enclosed a sample of our product for your review.
Informal:
* I've enclosed a photo of my cat, he's so cute!
* The book was enclosed in a protective sleeve.
* He felt enclosed by the towering walls of the building.
Figurative:
* The city felt enclosed by a thick fog, making it difficult to see.
* She felt enclosed by her own anxieties, unable to escape.
As a verb:
* The brochure was enclosed in a plastic folder.
* The box was carefully enclosed with a ribbon.
As you can see, "enclosed" can be used in various contexts, both formal and informal. It's important to choose the appropriate usage based on the context of your sentence.