ANSWER:
The correct sentences are:
1) Friday is the deadline to submit applications; if you are interested in the job, submit your resume soon.
2) She said: "Check in the file cabinet because it might be there."
3) All six work groups’ status reports were due on April 23.
EXPLANATION:
1) semicolon are use to join two related sentence. Because the two sentence are related, semicolon can be used.
2) are used to show list of items or what someone said. The quotation marks was use to indicate what a person has said.
3) The apostrophe is used to indicate ownership. It is used in this sentence to show the ownership of the group which is plural.