If you have used a Wizard to create a form, you may recall that at one point the Wizard will ask you to pick a format from a few that are included in Access:

 

 

If you feel you want to use a preformatted style in Design view, but have already put a lot of work into the design of a form, you can choose from one of the included themes by clicking the AutoFormat icon () in the Form Design toolbar:

 

  

Click a theme and then click OK to apply it to your current form. In addition to selecting a format, you can modify certain elements of an existing theme. Click the Options button to decide which elements to modify:

 

 

Then, click the Customize button to modify elements of the theme:

 

 

Choose an option and click OK, then adjust the elements as you see fit.