How to toggle customize invoice

Hello, Kazuko. Customising your invoices boosts professionalism, strengthens your brand, and enhances customer satisfaction. Through our collaborative efforts, we can achieve your goal.  

You can click the Customise option on the Invoice page to select your preferred style and add a new one. Please see the attached screenshot for visual reference.
 

I have replicated this matter on my end. I managed to customise the invoice. Since you're having challenges selecting it, we can perform basic troubleshooting steps to rectify this. It could be that you've accumulated too much historical data, which leads to unexpected behaviors.

Let's access your account through an incognito window to rule out the possibility of a webpage issue. You can do this by using these keyboard shortcuts:

• Google Chrome and Microsoft Edge: Ctrl+ Shift + N
• Mozilla Firefox: Ctrl + Shift + P
• Safari: Command + Option + P
   

Once you can click the Customise button and choose your style, please return to your regular browser. Then, clear your cache to start fresh. You can also switch to other installed supported browsers, which is a good alternative.

Moreover, you can refer to these resources for assistance with managing your sales forms and creating custom form styles.

• Customise invoices, estimates, and sales receipts.
• Add, customise, or remove logos on sales forms. 
• Import custom form styles for invoices or estimates.

I'm eager to hear how things worked out following the troubleshooting steps. My goal is to ensure you get the help you need. Much success to you!