This guide will show you how to create .zip archives using 7-Zip. This can be useful for uploading files and folders to your server, because .zip files are compressed and therefore smaller and not every software can work with folders.
Start by downloading and installing it, if you don't have it installed already. Then download/create the folder/file you want to upload and right click on it in Windows Explorer.
Then select 7-Zip -> Add to "nameOfYourFolder.zip"
And your .zip archive is now ready to be used.