Questions form a new Linux user

Sirs,

I used Microsoft Windows all my life.
But because of very bad experiences with  Microsoft, or organisations or
persons having access to my pc via Microsoft, i now bought another pc with
only LinuxMint os on it.
The harddisk was removed and an SSD was installed.
At first sight there should be no trace of Microsoft on that pc, and i did
not connect it to the internet (yet).

My questions :

1 Will there be an automatic link via LinusMint or Libreoffice  to
Microsoft, when i connect this PC to Wifi ?

2 Writer :
To test this PC, i first created some files and text-documents.
Only after that i found LibreOffice and Writer,
meaning that i created these files and documents with the Mint-textprogram.
But is there a way to move these texts and files to Writer ?

3 in Writer i cannot create files, only documents.
   The pictograms '1 file higher' or ' create a new file' as mentionned in
'help' for Writer, are not available in a document i created on Writer.

4 Before buying this PC, i found inforation on th internet about Linux /
LibreOffice, that one of their big advantages is that a document can be
'saved' in PDF, but i could not find that PDF option for saving a document
in Writer.

5 Can i upload PDF documents fia a USBstick to Writer ?

Thanks for your help.
Leo
evens.leo@gmail.com