I've come to help record your business-related expenses and employee reimbursement in QuickBooks Online (QBO), @bhuvaneshwer-pra.
For your first question, you'll have to create a journal entry (JE) to clear or close the purchase bill you've recorded. With this process, I'd recommend consulting your accountant to help you select the appropriate accounts. Whenever you're ready, follow these steps:
You can get more details about the process in this article: Resolve A/R or A/P balances on a cash basis Balance Sheet.
Then for your second question, you'll have two options to reimburse the employee for paying a purchase bill. You can either opt to pay them now or at a later time.
If you want to pay the employee now, you can create an expense transaction and select a liability account. But if you want to record the expense first and pay the employee later, you can create a journal entry for it. For the step-by-step guide for each procedure, you can refer to this article: Reimburse an employee.
Once you're done, you can pull up and customise a supplier report (i.e., Transaction List by Supplier) to view all payments made for them. Then, a Transaction detail report (i.e., Transaction Detail by Account) to check your employee reimbursements. You can run the reposts by going to the Reports menu's Standard tab.
Let me know if you have other questions about recording business expenses and employee reimbursements in QBO. I'm just around to help. Take care and have a great day!