digital signature image on the invoice. or any pdf or printed file.
Is this a question? If so, what exactly are you asking? If you are asking how to include an image of a signature on an invoice, you could do that with a custom field. See https://guides.manager.io/8941 and https://guides.manager.io/16188.
Why are you showing us this image? Your question was already answered. From your other questions on the forum, I get the impression you are not reading the Guides.
@manishkumarshivam the PO number field can be visible when Purchase Order tab is active. Search in the guide.
for Signature lookup via Forum’s search engine. This subject already been discussed and there is user given code example to do it. one of the keyword is ‘markup html’.
what we do is , what some company did, saying “computer generated signature will not be present” will make more impressive.