This article describes how to create and send ZIP files in Windows.
Create a zipped folder to email multiple files as one attachment (Windows 10)
Select the files and/or folders you want to compress. They will be highlighted to indicate that they are selected. Right-click on one of the selected items and go to Send to > Compressed (zipped) folder.
Give the file a descriptive name so the recipient can easily understand what the folder contains. For example, if the ZIP file contains vacation photos, name it something like Vacation Photos 2021, not something obscure like the files you wanted or photos.
Attach the file and send it in your email client, just as you would with any other file.