If you wish to unsubscribe from any of my email lists, there is an unsubscribe link in each email. Or, if it is easier, forward one of the emails to me and I can sort it for you.
If you wish to stop notifications from this website popping up in your web browser or on your smartphone (which appear if at some point you’ve clicked/tapped on the option to receive browser notifications when visiting my site), then that is a local setting on your device/browser so it is something you’ll need to turn off at that end.
The exact details depend on the device/browser that you are using but this guide will step you through what needs doing.
There are also some other pretty clear sets of instructions if you Google something such as “how to turn off web browser notifications on smartphones” or “how to turn off web notifications in <insert name of web browser you use>”.