Follow below mention steps to change the background color of the design :
Step 1 : Go to Appy Pie Design
Step 2 : If you have an account login to your account, else create an account
Step 3 : Create or open an existing design/project
Step 4 : Go to the “Background” tab present on the editor’s side panel
Step 5 : Choose a color from the color palette or use the + button to pick a new
color
Step 6 : You can select the color by simply moving the cursor in the color window
Step 7 : Your selected color will be applied on the design