Well, using the insert image option and draw option you can insert your signature in Word for free. You can also get add-ins in Word like “DocuSign” that support Microsoft and add reusable signatures. There are many applications on the web as well that can be used to attest your document for free. One of them is “DigiSigner” which is free and pretty easy to use. For signing pdfs you can make use of “Adobe Acrobat Reader”. To sign pdf on your mobile phone you can make use of the “Adobe fill & sign” app.