Here’s a tech basic that I think is worth going over. What’s the difference between Save and Save as?
I bring this up because I ran into a rather bright young fellow who actually didn’t know the difference.

Well, to put it simply, Save will save the current file under the same name in the same location. (Meaning it saves the new changes over the original file you opened.) If a file is newly created then Save will open a window allowing you to name the file and choose a save location. Otherwise, it’s a simple save of the current information over the old, in the same place with the same name.

On the other hand, Save As will always bring up the Save As window allowing you to change the file name and its save location. Assuming you make a change to name or location, the original file will still be intact in its original location after the Save As.
When you select “save as” you can also select what file format you want. Example; choose to make it a pdf?? That is in the case of documents I think. So you could end up with a document in 2 different format. ?