Password Protect not available on my desk top Adobe Acrobat Reader DC (64-BIT)

Hi Fariha,

sorry for the delay in response to your question.

Adobe Acrobat Reader DC is freeware. Password Protect option is available with the paid product Adobe Acrobat DC. It is not accessible with the Adobe Reader DC.

For more details on this, you can refer to this article: https://helpx.adobe.com/acrobat/how-to/password-protect-pdf.html?set=acrobat--fundamentals--secure-pdf 

~Akanchha