Both Uses of

correspond

in

Starship Troopers

He's the most junior officer and has the extra jobs — athletics officer, mail censor, referee for competitions, school officer, correspondence courses officer, prosecutor courts-martial, treasurer of the welfare mutual loan fund, custodian of registered publications, stores officer, troopers' mess officer, et cetera ad endless nauseam.†
Chpt 13

correspondence = done from afar

Correspondence courses meant a lot of paperwork since quite a few were continuing their educations, war or no war — but I delegated my platoon sergeant and the records were kept by the PFC who was his clerk.†
Chpt 13 *

Definitions:

(1) (correspond as in: corresponding time period)
connect or fit together by being equivalent, proportionate, or matched

(Two things are equivalent if they have the same or very similar value, purpose, or result.)
(2) (correspond as in: corresponding by email)
communicate -- typically by writing letters or email

A corresponding secretary is an officer of an organization who is responsible for managing the organization's correspondence and keeping a record of it.
(3) (correspondence as in: a correspondence course)
done from afar

For example, a corresponding member or a correspondence course.

This sense of corresponding arose because people who lived in distant cities and could not be present for meetings, could communicate by sending written communications.
(4) (correspondent as in: foreign correspondent of the paper)
a reporter or other representative -- typically from a foreign country or with a particular expertise
(5) (meaning too rare to warrant focus)