Hi and welcome to the forums.
OOo can create PDFs by using the PDF button on the toolbar (next to the Printer in Writer) or by using File > Export...
However, In it's 'out of the box' state it can't open or edit PDFs. There is an extension you can get from here
PDF Import Extension that will allow you to open PDFs in Draw and Impress, and to make
small edits. It is intended for the fixing of a typo or something like that - it isn't an all singing, all dancing PDF editing tool.
If this has answered your question please go to your
first post and use the Edit button, and add [Solved] to the start of the title. You can use the green tick icon at the same time if you like.