Cannot open my letter: get error C:\Users\latha\AppData\Local\Packages\Microsoft.MicrosoftEdge_8wekyb3d8bbwe\TempState\Downloads\J&J Fireplace replacement letter.odt does not exist.
Does the file exist? Have you checked?
If it does exist, then it is a permissions/access issue.
Please, in the future try to make a more readable and informative text for your question.
Judging by the file path it seems that you saved in a folder for temporary files, so that the file may have been deleted after closing Libre. Don't save files in folders that aren’t in your own Windows user folder (only in your User\My Documents folder if you are new to computing).