Open your Google Docs document
Place the cursor where you want the signature
Click Insert
Select Drawing
Click New
Click the Line tool and choose Scribble
Draw your signature with your mouse or trackpad
Click Save and Close
Resize or move the signature if needed
Alternatively, insert a signature image by clicking Insert
Select Image
Upload from computer, Drive, Photos, or by URL
Select the signature image and insert it into the document
Adjust the image size and placement as needed