SharePoint by default converts all space characters entered for the URL name are converted to a "-" sign. This is actually a good idea as reading something like "My-shopping-cart.aspx" looks better than "My%20shopping%20cart.aspx".
If there is a need to include space characters in the URL, it can be enabled by below mentioned steps.
Navigate to - "Site Settings" - "Look and Feel" - "Page Layouts and Site Templates" - scroll down to the bottom and change the "Convert blank spaces in page name to '-'" option.
