How to add a link to my e-mail on my taskbar?

If you did not find anything then go to the older version of windows.

usually done thru the browser with an extension

So if you hate Win 10, don't use it but install a Linux instead. I can recommend Linux Mint as being closest in looks to Windows to not leave you feeling completely helpless.

Try any of these methods:

1)Go the start icon to reveal the mail app. Right click on the mail app, choose pin to taskbar

2)Drag the mail icon from the desktop to the task bar

3)If you are using your browser to access the mail then temporarily make the browser half screen, click and drag the address bar onto the desktop to make a shortcut icon and then 2)