Hi, jaya. Thanks for joining us. Welcome to English Forums. As you can see, I'm not an expert.
"I have a pen." is
transitive.
"A pen is had [by me.]" is
passive. (If "have" were not transitive, we couldn't make the "passive transformation.")
Sorry about the patternizing.

The only example I can think of offhand where "to have" is used intransitively is in the old song, "God Bless The Child":
Mama may have; Papa may have. But God Bless the child who's got his own. I'm sure there are others.
Best regards, - A.