I want to add hyperlink instead of a long link in my email template

Instead of this big link
/sharepoint/start/Raman/Process/Onboarding/Testfile/Demo/Book.xlsx a short link

You have to use anchor tag. It works like as below

image|226x22

replace the Path with the link or path you want to provide and Name with the hyperlink text you want to represent it with.

And check the Html Body flag True in properties panel.