Standard text in ‘Write Post’ field

Hello
When I click on Write > Post, I want a standard text in my Write Post field.
Something like < a href=”link”>Watch video in the HTML field.
So that I don’t have to type it each time because my posts have always the same structure.
I’ve already looked in a lot of files, but I can’t find a solution how to do this.
I hope anyone can help me with this.

Thanks