Made a mistake choosing Bangladeshi "Taka" as Home currency while also turning on the "Multi-currency"; Problem: i'm about to entry different currencies which i now can't

Once Multicurrency is on and your Home Currency is set, QuickBooks Online (QBO) locks that home currency permanently. Since you already turned on multicurrency, you can create foreign-currency transactions after you assign a currency to the customer. 

To add a new customer, follow these steps:

1. Go to All apps and select Customer Hub.
2. Click on Customers & leads, then choose New customer.
3. In the Customer information window, select the desired currency from the Currency dropdown menu. This will be the currency the customer uses to pay for your products or services.
4. Complete the required information and click on Save.

If you have any questions or need further clarification, please let us know below.