In this simple example lets test adding rows to a sheet based on the notifications you receive.

STEP 1 - SELECT APPS TO LOG NOTIFICATIONS

• Create a new Profile
• Use the Event > Notification condition
• Select the apps you want to log notifications of. In my example, to make it easy to test I used Join and AutoNotification
• Accept and create the task

Important (not in video): in the task, click its Settings button on the top right and change Collision Handling to Run Both Together so that even if notifications arrive very close to each other they'll still get logged

STEP 2 - STOP IF NO TEXT AND GET APP NAME

• Add a Stop action and set its If condition to %evtprm(3) is Not Set

This will make the task stop if the text of the notification is not set so we ignore notifications with no text. We know that %evtprm(3) is the text of the notification because on the Notification Event configuration screen, the Text field is the third one from the top. This same rule applies for all events in Tasker

• Add an App Info action and set Package/App Name to %evtprm(1) which corresponds to the app's package name. This will allow getting the app's name in the %app_name() array

STEP 3 - SEND NOTIFICATION DATA TO SHEET

• Add an AutoSheets Add Rows action
• Set the Spreadsheet ID to the ID of the sheet you want to log your notifications in (use the helper to set it easily)
• Set the Data field to
  Code (Text):

  %evtprm(1)###%app_name(1)###%evtprm(2)###%evtprm(3)

We're using the ### separator so that if the notification's title or text has a comma, the data will not be wrongly split. If you want to be extra safe use a splitter that you think will never ever appear in a notification. I think ### is safe for probably 99% of cases
%evtprm(1) is the notification's package name, %app_name(1) is the app's name, %evtprm(2) is the notification's title and %evtprm(3) is the notification's text

• Set the Separator field to ### so that the data is correctly split

STEP 4 - TEST

• Save your setup
• Create a new task with an AutoNotification action and create a test notification
• Check that it's saved on your Google Sheet
• Create a remote notification with Join using the Note To Self feature
• Check that it is also saved to your Google Sheet

You will now get a log of the notifications in your Google Sheets so you can do whatever you want with them!