Envelope printing refers to the process of printing designs, logos, text or other graphics on envelopes. It can be done using offset printing methods. Envelope printing can be done on the front, back or flap of the envelope and is often used for personal or business correspondence, invitations, promotions or advertising.

Envelope Types:
Regular/Standard Envelopes: The most common type, usually rectangular, with a flap at one end for sealing.

Business Envelopes: Similar to regular envelopes but have a more professional look, often with a plain or printed design.

Window Envelopes: Have a clear plastic window on the front that allows the recipient's address to be seen.

Security/Tamperproof Envelopes: Features such as a colored interior or a patterned adhesive that indicates whether the envelope has been opened.

Catalog/Booklet Envelopes: Get a larger cover and a square base that allows them to hold multiple sheets of paper or small booklets.

Bubble Envelopes: Made from a padded material and have a bubble inside for added protection during shipping.

Tyvek Envelopes: Made from a durable, synthetic material that provides tear and water resistance.

These are some of the most common types of adverbs. Envelope selection depends on the sender's specific needs, such as the size and type of content, security requirements, and budget.