How can I officially deposit a check and we able to use the funds

You'll need to officially deposit a physical check into your linked bank account first to use the funds, civilconcrete.

Please note that QuickBooks Online (QBO) allows you to track and record your deposits. However, to access the actual funds from a physical check, you must first deposit it into your bank either in-branch, at an ATM, or via your bank's mobile app. Once you've made the deposit, remember to record it in QuickBooks Online by creating a bank deposit to ensure your financial records remain accurate.
 

Here's how you can create a bank deposit:
 

1. Go to +Create, then click Bank deposit under the Other column.
   
2. Choose the bank where you deposited the check in the Account.
3. Select the received payments or undeposited funds that correspond to this check so you can match your deposit to the actual funds in your bank.
4. Once you're done, click Save and close.
   

You can also check out this article for detailed information about creating a bank deposit in QuickBooks Online: Record and make bank deposits in QuickBooks Online.

Just in case you need more guidance when accounting or doing other QuickBooks-related tasks, our QuickBooks Live Expert Assisted Team is always ready to help.

Please post again in the Community forum for other questions, and we'll respond promptly.