I have seen ads for this on social media sites. If you don’t have horrible handwriting like I do, you can make your own custom logo easy. This process can work with a tradition logo as well. The main ingredient is a Wacom tablet. It would be difficult to write with a mouse but doable.
First, you need to create a blank white document. White is key to make your own brush in photoshop you need a white background and your subject, in this case, your signature to be black. Basically, we are creating a brush. I have all kinds of brushes that I use in special effects in Adobe Photoshop CC 2017. Then simply write in black and you are done. Go to edit/define brush preset, give it a name and you have your custom watermark or logo. I have created a video on my YouTube channel, to show the process.