You want to be able to easily design forms for SharePoint, so you need to install SharePoint Designer.
Microsoft offers SharePoint Designer as a free download.
- Go to the SharePoint Designer 2010 32-bit download.
- Download the software. It’s a roughly 250 MB download.
- Install the software on your local PC.
If you are a glutton for punishment like me and installed Office 64-bit, then you need to download the 64-bit version of SharePoint Designer.