Time to do this: 3 minutes
There are a few things to check to get Quick Edit enabled on a SharePoint list. Very simply:
Check multi-line text fields and make sure they are set to plain text.
Check and ensure the view settings have “allow individual item checkboxes” enabled. This should be enabled for any list view you want to have Quick Edit available for.
In Advanced Settings for the list, make sure “Quick property editing” is set to Yes.
These are the most common solutions when the Quick Edit option is grayed out. Depending on the version of SharePoint you’re working with, there may be other column type limitations, like Managed Metadata, etc.