Is there a Good Free App to Create And Modify Spreadsheets And PDF?

Is there a good free app to create and modify spreadsheets and PDF files for old Android phones like Galaxy Y that have a very low memory?

You can put pdf files on your Android phone by multiple methods. The following are a few simple methods; Using a cloud storage such as google drive or one drive, Emailing yourself the pdf depending on the file size, Sending your self the file over whatsapp, Sending the files over Bluetooth. If you can provide more details, better help can be provided. For example where is the PDF file stored, what size is the file, what type of android device (optional)