plagiarism can be avoided using paraphrasing, citing, quoting, and referencing for formal documents.
For less formal documentations,
You may use attribution by giving appropriate credits like name, links and etc.
(Based on the least strict license available, and depending on the university for your course)
For my recipes, I put
Many recipes website did not even put.
For softwares, there are GPL, LGPL, and etc. license that may need to be adhere if stated by the author.
I have developed the WriterHelper software at https://sourceforge.net/projects/writerhelpersoft/
WriterHelper consist of WordNet Dictionary, WordNet Thesaurus, Plagiarism Checker, Encryption using TripleDES, DES, and AES.
WriterHelper helps you to search for the dictionary, thesaurus using WordNet Dictionary, Encrypt Text using AES, DES, TripleDES, and Plagiarism CHecking.