Is this sentence:

"I don't know her in person; only by name."


I met her in person .= I have been in her presence (actually met her)..

I don;t know her in person.= I have not actually met her , (physically).

I know her by name. = I know her name (her name identifies her)

e,g I don't know Donald Trump in person only by name.

= I have never physically met him but I know who he is by hearing his name. (his name identifies him as the USA president).