I have purchased the themeforest-14728833-jevelin-multipurpose-premium-responsive-wordpress-theme.zip, but in the upload of the theme the installation fails, as reported in the attachment. The WordPress version is 4.9.5. The error says that in the zip style.css is missing
Sorry to hear of the problem you are having.
It seems you are trying to install wrong zip file.
You can install the theme zip file as described in the following page.