The following article introduces you in detail how to create a color effect in PowerPoint.
Step 1: Go Card Design -> Customize -> Format Background:
Step 2: Format Background window appears -> in the Fill section, select the background color in the Color section :
Step 3: In case you want to select multiple colors, click More color -> dialog box appears to choose the colors to coordinate -> select OK:
Step 4: Select more effects for the background color by clicking Gradient Fill -> select the effects in the Preset gradients section:
Step 5: Create additional background effects by clicking Pattern Fill -> selecting the background style in the Pattern section :
Finally, click Apply to All to apply the styles set to the slide:
The above is a detailed guide on how to create a color effect in PowerPoint.
Good luck!