If you want to add or change functionality in an open source program, you can upvote it in a couple of ways.
First do your research to understand if the request is already implemented or maybe there are some good workarounds to your problem.
If not, then search the bug list to see if the problem or enhancement is already described. I would like to see the search functionality in Libre Office Calc to search in values instead of in formulas. The bug has already been described: https://bugs.documentfoundation.org/show_bug.cgi?id=115538
To upvote the the enhancement or bug, say you can replicate it or you are having the same issue and add yourself to the CC list.
You can also probe the question at ask.libreoffice.org. For example: https://ask.libreoffice.org/en/question/64352/how-can-change-the-defaul…
Happy requesting and respect the developers at all times. Most of them are using their spare time to develop these programs.