How do I change a line of print from lower case to upper case?

Occasionally I want to capitalize a line of print.
Where do I find the controls?

Also, How do I find previously asked questions. Someone answered, but it did not work. I continued searching and finally found how to reduce the size of the margins at the top and bottom of the page.
Format-Page Style-Page_ controls to adjust all margins. Eliminating header and footers does not reduce the margin.

To find your questions in ask.libreoffice.org, click on your username (in the top of this page).

Select your text. Click Format > Text > Upper Case.

You could also do it as a Character Style. With the test selected, click Format > Character, in the dialog that opens select tab Font Effects and under Effects choose UPPERCASE.

Keeping the text selected, in the sidebar click on Styles icon then select Character Style (second icon from left above the pane). At the right there is an icon with the tooltip Styles actions, click on that and select New Style from selection, give it suitable name and OK. The advantage of a character style is that if you subsequently decide you want to change it to, say, Capitalise all words and Bold, then you can just change the Character Style and all instances in the document will change to reflect your new preferences. Cheers, Al

And you can put the icons of the Uppercase/Lowercase function onto the primary toolbar. Just use the Customize feature.

Take note that menu Format - Text - UPPERCASE will convert your text to uppercase, while menu Format - Character… - Font Effects tab - Case: UPPERCASE will show your text as uppercase. You will notice the difference when copying and pasting the text.