Signature question

I need to find a way to force the signature to be bold as is too thin and when we print out the documents it can barely be found i know if they draw the signature this could help i also now if they upload their own signature this would work out i i don't know how to force the fonts to only be the boldest ones so once they are selected they could be more legible. all the suggestion to mitigate are much apreciatted.