Hey there,
As per your requirement, to send a document for signature you would required subscription service to do that.
You can get documents signed by others using the Send for Signature tool, which relies on cloud services provided by Adobe Sign. This service you can get in Acrobat DC, Adobe PDF Pack and Adobe Sign subscription.
Here are the help articles which describes how to access this service from desktop application Acrobat DC and Document Cloud web
Answer to your further question, when you send the document for signature and setup a signature filed for the end user. You can restrict the document properties to make further changes like, editing, changing content etc.
Click here to know Restrict editing of a document
Hope this answers your query.
Thanks,
Akanchha