Well since I dont have photoshop or any other kinda tools I use paint, been using it for several years now. Just made a new signature a couple of days ago. Just got a picture of a cow on google, then hand drew it using pencil on Paint (pixel by pixel) same with others but after that simply used the Bucket to fill in and worked with pencil on removing the white spot.
This is the final result I came with:
Since Paint dosent have cool font or any other kinda effects, I left it as it is ;)







