Add fillable fields to documents for signature with C# SDK using the API

Add a signature, text, initials or checkbox fields. The SignNow API allows users to transform a static document into a fillable form within one application.
Want to embed e-signatures into your workflows?
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Make static PDF documents fillable
Use the sample code to add one or many fillable fields to text or image-based PDF files and make them editable.
  • We provide developers with complete SDKs for all popular languages, allowing them to integrate e-signature workflows without writing a single line of code.
  • With our detailed documentation, integrating the signNow API is a breeze.
  • The signNow API not only provides you with e-signatures: use it to create fillable forms, request payments, and download & archive documents using simple API calls.
Watch the signNow API in action:

Start using the signNow API with any of our SDKs

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