There are two types of form fragments requirements in my project:
1. Header and Footer: Content authored once, but used in all forms
2. Common parts of a form: Here it has a set of form elements common in many forms, but content should not replicate. Every form should be presented only those fields with blanks (no values). Ex: Address.
But a Form Fragment once authored, will bear that content correct?
You mentioned "AEM Forms follow similar notion of creating templates as done in AEM Sites.".
In AEM, if the template has iParsys, if I author header & footer to a page at a folder level, all the child pages underneath that page inherit those header and footer.
But in Forms, where is the concept of parent page, iParsys, child page and all child forms inheriting all iParsys elements from parent?
By similar notion, I meant the way templates are created. Components used in the template would be different in both Sites and Forms.
Just like "parsys" in sites, we have "panel with grid fluid layout" in forms. In fact, grid fluid layout of panel behaves very similar to parsys. If you start using the template editor in forms, you would get answers to your question.
Forms does not have the notion of parent and child. If you wish to re-use content across forms, you could make use of Adaptive Form Fragments.
If the header and footer are the same why not create a template with the header and footer or create form fragment header/footer elements. Using fragments allows you to modify them as needed and have the changes replicated automatically across forms.
AEM Forms follow similar notion of creating templates as done in AEM Sites.
In 6.2, a new feature of template editor was added in AEM. With this, you could actually create editable templates(template created using template editor) as detailed here . You could also refer to a video tutorial at 
If you are using 6.1, you could follow steps mentioned here . Please Note, these templates are static template meaning, they don't have any editor for authoring them.
Template editor is very powerful and there are many new features added. More details can be found at .
Hope the links mentioned below help you easily create AEM Forms Template. Let me know if you have any further questions.