It is important to understand that once a template has been used to create the first "real" document, you should refrain from making ANY updates to the template. This is because the S-Docs template record is used both during document creation AND during each subsequent view of an S-Doc. Each S-Doc stores the template used to create it. If you attempt to open an S-Doc where the template used to create it has been deleted, you will receive an error. The diagram below illustrates this relationship.
If you want to make changes after you have completed your design work, it will affect how PREVIOUSLY generated documents are rendered. Therefore, if you need to make changes, you should CLONE the template and make modifications to the newly cloned record.
You then uncheck Available for use and Initially Visible on the original template to ensure no new document can be created using it.
Previously generated documents will continue to use the original template (therefore rendering unchanged), and new documents will use the newly activated template.
Discussion: To maintain flexibility during the iterative process of template design, and to allow for mass changes to previously created documents, it is advantageous for some to be able to edit templates after first use. However, for many organizations it is equally important that documents are not changed once created. For example, a contract created a year ago should not be affected if you updated the Terms section of the S-Docs template record. If you follow the technique described above, you can ensure that your documents maintain an unalterable point-in-time record.
Alternatively, you can also use the Auto Create Salesforce Attachment and link to record option (found under the "Document Options" tab in the template editor, this feature is enabled by default). This is particularly useful for orgs that are restricted to 2 templates, have a need to change templates often, and still require past documents to remain unaffected by future template changes. Attachments allow you to store a copy of the document that cannot be affected by template changes and do not require the S-Docs template record to view.