noun
Refers to the person who creates or authors something, especially documents, software, or formal works. More specific than 作者 (which leans toward artistic works) and 著者 (which leans toward written publications).
この書類の作成者は山田さんです。
The creator of this document is Mr. Yamada.
ソフトウェアの作成者に問い合わせてください。
Please contact the software's author.
著者 specifically refers to the author of a written publication (book, article). 作成者 is broader and can include non-literary creation.
Compound of 作成 (sakusei, 'creation, preparation') + 者 (sha, 'person'). The reading is regular on'yomi.