To ensure the authenticity of a document you have to sign the document with the certificate. I will show you how you can easily sign PDF document with the help of simple tool DigiSigner.
In Gmail there is no insert/upload image option by default. Let me show you how to enable the option so you can upload and insert an image into the email or insert an image by providing url.
Microsoft Word allows you to add the comments to text, images or basically anything included in the document. It's a great way do review a document and suggest the changes that should be made.