How can I recover accidentally deleted document?

trying to recover a libre office ods. file.

If deleted in a file manager, try Ctrl+Z immediately

If you have a recycling bin, look in there; if it is there follow your OS instructions on how to restore the file.

If you have enabled backups in LibreOffice, have a look in the backup folder for [filename].bak.

Backup folder is defined in Tools > Options > LibreOffice > Paths. The default location is a sub-folder of the user folder, see Default locations.

Consider implementing a backup policy, possibly combined with a version policy for important documents. Cheers, Al