If you want signature like this:
Kindly follow these steps:
1. Find out where are your signature, right click on it > Properties and copy the path and name.
2. Open Book Keeper > Settings > Template Settings > disable Display Company Signature.
and in Footer > Authorized Signatory.
There you need to write like this:
For the company
if you see carefully, C:\Users\rohit\Desktop is the path, which we have copied in step1, and then add \ and then write file name.
3. Save it and view your invoice.