https://www.digitallearn.org/ ​Contains relatively short (usually < 20 min) workshops how to do basic things on computers
https://support.microsoft.com/en-us/office/basic-tasks-in-excel-dc775dd1-fa52-430f-9c3c-d998d1735fca Microsoft's website for basic tasks in excel
https://support.microsoft.com/en-us/training Contains instructions on how to work all of the Microsoft's current products
https://www.computerworld.com/article/3193992/excel-2016-and-2019-cheat-sheet.html Article discussing tips for using excel
https://www.excel-easy.com/ Website that discusses some of the basic operations of excel and how to do them.
https://nscc.libguides.com/Onlineworkshops/word Word and PowerPoint tutorials with other related links.
https://edu.gcfglobal.org/en/subjects/tech/ Website with very good tutorials for just about anything technology related (Word, PowerPoint, Excel, Google Sheets, Access, Online Safety, Mac and Windows operating systems, etc.) with quizzes at the end.
https://www.free-training-tutorial.com/excel-tutorial.html Free Training Tutorial page for excel
https://support.microsoft.com/en-us/office/excel-functions-alphabetical-b3944572-255d-4efb-bb96-c6d90033e188 Microsoft's complete list of functions.