会社 and 社会: a company and society
Distinguish the readings and meanings of two words with reversed characters.
The organization called a company
会社 (かいしゃ) means a company. 「会社で働いています」 says that the speaker works at a company, with で marking the work location.
「会社に連絡しました」 means contacting the company. It does not necessarily report a physical visit to the office.
The wider society
社会 (しゃかい) means society, where people live in relationships with one another. 「社会の変化を学びます」 means learning about social change, not merely one company's internal rules.
「社会に役立つ仕事をしたいです」 expresses a wish to do work useful to society. It describes desired work, not established employment at a particular company.
Character order and meaning
会社 and 社会 reverse the character order and are read かいしゃ and しゃかい. 「会社と社会の関係」 means the relationship between companies and society, with both scopes in one phrase.
「会社の問題」 concerns the company's problem, while 「社会の問題」 concerns a social problem. The modifying noun changes the scope of the same 問題.
Is a 「社会人」 necessarily an employee of a particular company?
Show the answer and why
No. In ordinary usage, it usually refers to someone working and living in society, in contrast to a student; it does not mean only an employee of a particular company.