I dont have word but will check out the libre
Note that it is a full office suite, so there is a word processor, spreadsheet application, presentation software, graphical drawing program. Once it is installed, you will want to open the word processor, named "Writer," and choose "File" in the menu at the top. From that dropdown menu, hover over "New" and then select "Labels" from the menu that pops out. You will get a box where you enter the text and choose the brand and type of labels you have (hopefully it is in the list). You can set a few options there like how labels many to print, and then click "New Document." Now you will have the text on each label. You can then change each label by adding or deleting text, formatting fonts, and even pasting in pictures.
I highly suggest printing some to a piece of regular paper as a test to see if everything lines up before printing the labels.