If you are having trouble enabling forms for Reader users, check the following conditions:

Reader-enabling forms option is unavailable in the Advanced menu

• This feature is not available in Adobe Reader. You must have Acrobat 9 Pro, Pro Extended, or Standard, Acrobat 8 Professional, or Acrobat 3D Version 8.
• If you are editing the form, click Close Form Editing in the upper-right corner of the form.
• Make sure that the security settings allow form filling. (See File > Properties > Security.)
• Make sure that the PDF/A standard was not used to create the file. (Check for the Standards panel button  in the Navigation pane.) If PDF/A was used, re-create the PDF without the PDF/A setting to allow reader-enabling.

Reader users cannot fill in or save the form

• Reader users must have Reader 8 or later.
• When you choose the Reader-enabling option, save a copy of the form using a different filename, and then send the copy to recipients.

Troubleshooting tips for completing forms

If you're having trouble filling in and submitting forms, check the following conditions:

• Make sure that the security settings allow form filling. (See File > Properties > Security.)
• Make sure that the PDF includes interactive, or fillable, form fields. Sometimes form creators forget to convert their PDFs to interactive forms, or they intentionally design a form you can only fill in by hand. If you can't type in the form fields, then the fields are probably not interactive. 
• Check for additional capabilities and restrictions in the purple document message bar, just below the tool area. 

Additional forms tips for Acrobat users

Additional forms tips for Acrobat users 

• If the form doesn't have interactive form fields, open the form in Acrobat 9 (any version) and choose Forms > Add Or Edit Fields. Check if this message appears: "Currently there are no form fields on this PDF. Do you want Acrobat to detect the form fields for you?". You can click Yes to run the Form Field Recognition tool, or use the Typewriter tool to create form fields.
• If the message "This operation is not permitted" appears when users open or submit your form, check for unembedded fonts or hidden objects. Also, make sure that fonts are embedded in any PDF before you import it as artwork in the form. To check for unembedded fonts, choose File > Properties > Font tab. To embed fonts, choose Tools > Advanced Editing > TouchUp Text Tool. To locate and remove content you don't want, choose Document > Examine Document in Acrobat. For more information, see the forum post Operation not permitted.
• If you have checked all these conditions and still can't fill out and submit the form, post your question on the Acrobat forum.

Additional forms tips for Reader users

• If the form doesn't have interactive form fields, you can ask the form creator to place form fields on the document. Or, you can download a free trial of Acrobat 9 (Windows only). In Acrobat, you can use either the Typewriter tool or Form Field Recognition tool to create form fields.
• If the form creator enabled additional capabilities, then the Document Extensions panel (View > Navigation Panels > Document Extensions) is available. You can open the panel to see what else you can do with the form. For example, you might be able to save and print data, add comments, and digitally sign it. 

If other functions, such as editing document content or inserting and deleting pages, are restricted, and you have checked all these conditions and still can't fill out and submit the form, post your question on the Acrobat Reader forum.