How can i add a generated qr code to a PDF document?

I'm creating an invoice from  an HTML  template then I'm converting it into a PDF but the  qr codes are nor being shown  in the document. I've tried many ways

the first one was   converting  this image into a base 64 image with a plugin called  "Base64 to Database Services"   this approach     didn't work for me 

this is an example of how i add the base 64 image  what i notice is that  if i a generate a base 64 with another platform it also gives me a kind of path

like  this

this is an example of how i place the generated base 64 image