Google Docs: Suggest edits (from Google's Docs Editors Help site)
Microsoft Word: Track changes (from Microsoft's Word Help & Training site)
Adobe Acrobat: Use annotation and drawing markup tools to add comments in PDFs (from Adobe's Acrobat User Guide)
Zoom: How do I share my screen? (from Zoom's Help Center)
Google Meet: Present during a video meeting (from Google Meet Help)
Matthew Butterick, Type Composition: This section of the Butterick's Practical Typography website has detailed information on how to use punctuation and includes advice for creating special characters in both print and electronic documents.
Mignon Fogarty, Grammar Girl: The Grammar Girl website has detailed advice on grammar, mechanics, and style for writers.
Karen Hertzberg, How to Give Writing Feedback that's Constructive, Not Crushing: This post on Grammarly's blog provides a short list of tips on structuring the feedback you give to other writers.
Duncan Koerber, 100 Editing and Proofreading Tips for Writers: This post on The Expert Editor blog gives a lot of good advice for proofreading your own writing and reviewing other writer's drafts.