In the sentence "I am glad to hear it" what is "to hear it"?

In sentences such as

"I am glad to hear it"

"I am ready to write down your address"

what do you call "to hear it" and "to write down your address"?

"I" is the subject, and "am" is the verb, right? Or are "to hear it" and "to write down" parts of the verb, too?

Side question: In a stenence talking to someone else, what do you call the other person in grammar? "I am ready, Mrs. Smith" - is Mrs. Smith an object?

1/ This is an adjective complement (ref.). So, "to hear it" is the (adjective) complement of "glad".

2/ This is an example of direct address (ref.).

In English grammar and rhetoric, direct address is a construction in which a speaker or writer communicates a message directly to another individual or group of individuals. The person(s) being addressed may be identified by name, nickname, the pronoun you, or an expression that's either friendly or unfriendly. Conventionally, the name of the person (or group) being addressed is set off by a comma or a pair of commas.