Hi
Your question is not clear but I try to answer.
من خوبم= من خوب هستم
کتاب من= کتابم
in first sentence, خوب+ام=خوبمmeans i'm fine. pay attention below:
من خوب ام-- تو خوبی--او خوب است
ما خوب ایم-- شما خوب اید-- انها خوب اند
These are instead of to be verbs in a short saying. We also can say من خوب هستم-- تو خوب هستی and so on
but regarding possessive "ام" it differs. It is short possessive like below
Singular Plural
am my emân our
at your (informal) etân your (polite)
ash his, her, its eshân their
his, her (polite)
Examples
Pedar-am — My father
Pedar-e khub-am — My good father
Ketâb-e dust-am — My friend's book