There are many ways in which you can make fillable PDF forms. One of the most common ways of making fillable PDF forms is by making the forms in Microsoft Word first and then converting the forms into PDF. You can use Microsoft Word or any other application which is similar to Microsoft Word to create the basic form. If you cannot afford MS Office, then you may want to use OpenOffice to create the basic word form. Some people say that OpenOffice is more powerful than MS Office. However, some people find OpenOffice to be not so user-friendly. This is the reason why most people choose MS Office over OpenOffice in spite of the fact that OpenOffice is free. But, once you get past the initial learning curve, you will simply love OpenOffice.
Once you create the basic forms in word, you can use any other software to convert them into fillable PDF forms. Adobe Acrobat Professional is the commonly used software program for converting a word form into PDF form. Unfortunately, Adobe Acrobat Professional is not a free software program. If you are looking for free alternatives, then you may want to try some free web-based options for converting word forms into fillable PDF forms.