Thanks for reaching out to the Community, @8 digit HSN Number. 

I can help you get the support you need about the HSN codes in QuickBooks.

Ideally, you should be able to enter 6 and 8 digits HSN codes into your products and services. If you've already followed the browser troubleshooting provided above, I suggest you proceed with contacting our QuickBooks Support Team.

Here's how:

1. Click the Help tab at the top menu bar.
2. Select Contact Us.
3. Enter your concern, then hit Let's talk.
4. Choose to Start a Chat.

Let me also share these articles with you for more reference about adding HSN codes in QBO:

• How to add HSN/SAC codes in QuickBooks for new products
• How to add HSN/SAC codes in QuickBooks for existing products
• How to upload HSN /SAC codes in bulk for existing products

You can click the Reply button below to add more details.

For tips and other resources, I recommend visiting our website for reference: Self-help articles.

Please know that I'm only a post away if you have any other questions. I want to make sure everything is taken care of for you. Have a good one!