A drawer.
The person who writes a check is called the payor. Or in the case of my brother, a sucker, when he writes another check for his girlfriend.
A person who writes a will is commonly referred to as the "testator."
A Philosopher
A person who writes the libretto for an opera is simply referred to as the librettist.
A poetry
publisher
proposal
It depends: a. No - If the spouse writes a check out of a single account held by the person writing the check b. Yes - If the spouse writes a check out of a single account that is held by their spouse and the person writing the check is not a joint owner of the account. To be simple: Writing a check from an account that is not held by the person writing the check is a crime.
A person who writes verses is a poet.
A columnist...?
Columnist
Author