Before you use a newly created form, you should protect it from being changed. After all, only the form objects are to be filled in and the form itself should no longer be able to be changed.
To protect a form, you have the following options:
Using form mode
If you enable the form mode presented in the Filling in forms section, you can only fill in form objects. The other parts of the document can then no longer be edited, and most TextMaker commands are no longer available.
Form mode can be enabled and disabled with the ribbon command View | Form mode 
.
Note: Bear in mind that users who fill in the form can disable form mode at any time unless you prevent them from doing so by locking form mode with a password (see below).
Saving the form in form mode
Tip: When you save a document in form mode, form mode is automatically re-enabled the next time the document is opened.
Locking form mode with a password
You can prevent other users from disabling form mode by locking it with a password.
To do so, choose the ribbon command File | Properties and switch to the Form tab. Enable form mode by enabling the option Form mode active. Then enter a Password to deactivate form mode and confirm with OK. Then save the document.
When a user subsequently opens the document and attempts to disable form mode, he or she will be prompted to enter the password. Thus, users will be able to disable form mode only if they have the correct password.
Tip: Saving forms as document templates
It is generally recommended that you save forms as document templates. This will always guarantee that the original file cannot be changed. When you have saved a form as a document template, you can use the ribbon command File | New to create new documents based on the content of this template without opening the template itself for editing.
For more information on using document templates, see Document templates.