I currently copy and paste from various places,documents,websites,what I am currently doing is pasting into my Libre Writer document,then control A to highlight the newly pasted section,then changing the font and size to suit,ie,so all the document is uniform…a bit of a chore to do this everytime,there must be a way to automate so that every time i paste in,it goes to say Ariel, font size 16,every time…if anyone has a solution can you tell me how to set this up in an easy to follow way ? Thankyou
There is a way, but you need to change strategy: instead of formatting afterwards, set the formatting before pasting and then paste “without format”, in this way the text will use the target format instead of its own.
Set the paragraph style on your target document with all the characteristics you want, then do a “paste special” to paste without formatting. To paste without formatting: Ctrl-Alt-Shift-V (yep, a four key shortcut) or Edit → Paste special → etcetera.
Thats great,thanks for that 
A little variant from RGB’s answer, if you want to retain things like Links, go ahead and paste regularly, not unformatted. Set up a paragraph style the way you want it. Now do your Ctrl-A, and impose the paragraph style on the selected text. You can do that easily from the Styles and Formatting sidebar, F11, or via the Formatting toolbar. Once you get the hang of para styles they save enormous amounts of time.
Nice one,cheers