I do not have access to the bank account online, how do I manually capture the cashbook

I appreciate you taking the time to raise your concern here in the Community forum.

As much as I'd like to help you manually capture your cashbook, it's already beyond our scope since you mentioned that you don't have access to your online bank account. To ensure that you'll get to have a list of your bank transactions, I recommend reaching out to your financial institution. This way, they can either give you access to your account or provide you with a CSV file to import into QuickBooks Online (QBO). 

Moreover, I'll also share this article that can serve as your reference if you want to learn how to review downloaded bank and credit card transactions and put them in the correct accounts: Categorise and match online bank transactions in QuickBooks Online.

I'm looking forward to getting this sorted out. Feel free to leave a reply if you have additional QuickBooks-related queries. The Community team always has your back. Have a good one.