This blogs focuses on how to add defaults to a SharePoint Customized (or PowerApps) form. The list in this demo includes all the column types including managed metadata. The video walks you through the steps in detail, however, this blog contains all the functions incase you want to copy and paste

This blog with the video walks you through how you can update filtered items in bulk. In this blog items bulk updates have been done in an Excel spreadsheet present in OneDrive, however, you can do the same for SharePoint lists or SQL tables.