A family of Microsoft relational database management systems designed for ease of use.
It depends to some extent on where and how you are trying to do this. The form should be opened in design view. You can also do some things in layout view, but that is less flexible and not as easy. It's for quick and dirty adjustments, not full design work.
You can open the Property Sheet as described in the AI answer using the Ribbon or a shortcut key. Then select the tab you need: Format, Data, Event, Other, or All.
The Property Sheet may pin itself to one side or the other of the Access window. I prefer it to be free-floating, but it's your choice.