Watermarks ~ How can the background of a watermark image be transparent?

Watermark problem ~~ How can the background of a watermark image be transparent? The text may not be clearly expressed. let's look at the example directly... this is what I want: this is what I achieve now: how does the background of the watermark image become transparent? The code is on the second floor... it's quite simple... get a transparent gif or png image! Score your brother! Hahaha watermark problem ~~ How can the background of a watermark image be transparent?
The text may be unclear...

This is what I want:


This is my current implementation:


Is the background of the watermark image transparent?


The code is on the 2nd floor...

------ Solution --------------------
It's quite simple... get a transparent gif or png image! Score your brother! Hahaha