Related Clues:

• Conjoin
• Connect
• Tag on
• Affix
• Link together
• Fasten on
• Paper-clip, perhaps
• Staple or clip on
• Sew on, say
• Include a document, as with an email
• Hook up
• Attribute (to)
• Email option
• Iron on, e.g.
• Staple or clip on, e.g.