There are a few ways on how you can manually enter your bank transactions, vibha.
You can do it by clicking the Create (+) sign and start a new sales form. Then, choose the bank account when creating a transaction.
You can also go to the Chart of Accounts page and choose the bank account to enter the bank transactions. For more details, just follow the steps in the Add transactions to account registers in QuickBooks Online (QBO) article.
If you want to manually add bank transactions, you can use the WebConnect feature. You'll need to download the data first from your bank's website and import them into QBO.
You can check out this article about manually uploading bank transactions into QBO: https://community.intuit.com/articles/1776029.
Please let me know if you need anything else with entering bank transactions. Just add more details by posting a comment below.