How do I customize invoice in BUSY with my company's logo, colors, etc?

If you want to add your company Logo on invoices, you can follow these steps. 
Steps for Standard format:
Step 1: Go to Administration and click on configuration tab.
Step 2: Click on Invoice / Document Printing and choose Standard.
Step 3: Choose the voucher type (such as sale, purchase, etc.) in that you want to add logo.
Step 4: Enable the Print Logo option by selecting Y, Browse and select the image file that contains your logo. Make sure that the image file is in JPEG format.
Step 5: Adjust the height and width of the image according to your preference. Choose the position of the logo on the invoice, you can select from Top Left, Top Right, or Top Centre options.
In standard format no option for coloring your text.
Steps for Advanced format:
Step 1: Go to Administration and click on configuration tab.
Step 2: Click on Invoice / Document Printing and choose Advanced.
Step 3: After selecting the voucher type in that you want to add logo (for example, sale or purchase, etc), you will see the name of your format below it.
Step 4: Clicking on the format name will allow you to add logo in header & footer parts.
Step 5: Now, you can select Image field by press on Print Styles button or press F4.
Step 6: Metnion your image file path that contains your logo. Make sure that the image file is in JPEG format. And mention the height and width of the image according to your preference.
For more customization like colors, etc you need concern with your authorized channel partner.
Note: Take latest backup of your date before making any changes.