More information is needed to know what you are talking about. Taking a guess, you have entered information into pdf based forms. Sometimes you can save the information you entered; sometimes you cannot.
By default Acrobat doesn't allow users to save data in pdf based forms. It requires the pdf files to be specially enabled by a either a Adobe LiveCycle product that is quite expensive or the creator must own a recent version of Acrobat and restrict the forms use to 500 uses and/or users.
If that is not the Q & A please leave more details.