I think you do need to provide more info as to what exactly you are hoping to accomplish.
If you are looking to build a form from ground-up, you will need to enable the "Developer" tab to gain access to the form controls.
The developer tab is not enabled by default, so you will need to click on the gear icon to the top right, and choose "Ribbon Preferences". Under the "Tab or Group Title" options, make sure to check the "Developer" option in order to show the Developer tab.
Click OK, and you should now have the Developer tab enabled. Feel free to use the form controls here for things such as text fields, etc etc.
Once your form is done, click "Protect Form", save as a normal Word document, and send it out to those folks whom you want them to fill up the form. They fill up, click the save button, and send it back to you.
Hope this helps - it can get quite complicated once you going into automated macros and other more advanced form capabilities of Word.