how do I add grid lines to my docs before printing.

always find difficulty adding gridlines to my docs before printing. What is the easiest & fastest way to add

You tagged your question common. Does it mean you want grid lines for Writer, Calc and Impress documents? Please give additional info editing your question (don’t use an answer reserved for solutions). Incidentally, mention LO version and OS in case it is relevant.

If somebody has a clear explanation how I should understand the term “grid lines” applied to something not being a spreadsheet, I would kindly ask for it.
There are drawing grids usable with every kind of document having a DrawPage (or more objects of the kind), but I can’t interpret consistently “grid lines” in this context.
Thus I assume the question is about spreadsheets in Calc documents and suiggest the questioner should change the tag to calc.

add lines in writer so I can print them

This is no answer to your question. By using a solution, you confuse users and contributors. In addition, you penalise yourself, letting others think that the question is solved and they would skip it.

As told, edit your question to bring more information and change tag from common to writer (click on the pencil icon next to the title). When done, delete your “non-answer”. Only you as owner of the question can do it.

  • In spreadsheets we have cells with lots of abstract properties, and the grid hosting the visual representation of these cells in the view. I’m exclusively talking about this cell-grid now.
  • Unfortunately there is a strange preference among some groups of users to not display the cell grid on screen mostly. This is a bad idea anyway because spreadsheets actually have cells we are working with, and which we must regard therefore.
  • On the other hand there often are reasons to not print this grid. After all the reader of a print does no longer work with the cells. He(f/m) may nonetheless need to recognize the “cellular structure”.
  • If this is the only actual purpose, we can introduce cell borders which not are “the grid”. Such borders always are printed.
  • If we want to emphasize that the origin of a print is a spreadsheet, we can also set the cell-grid printable per page style: Open the editing dialog via the menu or the stylist, and enable the respective field. The effect will be independent of the chosen view option.
  • If yoiu want to print the cell-grid there are no specific settings concerning the width (thickness) or color. Please tell me if you know better.

In Writer you can display a grid on screen by customising both Tools>Options, LibreOffice Writer>Grid and Tools>Options, LibreOffice>Application Colors. Note this will display the grid only on screen and the grid never prints.

If your intend is to simulate rule paper or grid paper, design your grid in a Draw slide. You’ll insert it as a background image in a Writer page (style).

  • create your grid in Draw, save the file
  • in Writer:
    • Format>Page Style to access the current page style
    • go to Area tab
    • import your Draw file
    • select it in adjust the parameters to your liking

Be aware that it is extremely difficult to “synchronise” the grid with text lines as background and text flow are independent from each other. You may somehow “quantize” line vertical positions by forcing register property (registering is a typography feature), but this is considered advanced usage. If you’re not familiar with styles, accept approximate results of the above procedure.