How can I charge tax from a different province than my resident province ?

You can charge taxes from different provinces by clicking the Enable Sales Tax option on your Invoice page.

QuickBooks Self-Employed defaults your tax settings to New Brunswick since this is your home address. To charge a different provincial rate, follow these steps below:

1. On the Invoice page, add your customer information.
2. Click Enable Sales Tax.
3. Choose how you want to charge your sales tax, then click Save.
4. Select the Nova Scotia sales tax from the Set sales tax rate dropdown.
5. Once done, add your item and click Add to invoice.

For more information, read this article: Sales Tax overview.

If you have other concerns, feel free to reach out.