You do not need a lengthy paragraph explaining why you pay or receive; you need concise information of what and where to explain the why.

Are advance payment, deposit, and prepayment any different?

QuickBooks Online does not have a salesperson field by default; however, you can create one.

Instead of having a job feature like QuickBooks Desktop, QuickBooks Online uses projects and sub-customers. Are they the same?

The account type can be a current assets account, and the detail type uses allowance for bad debts, which is available in QuickBooks Online (QBO).

The QuickBooks Online (QBO) import feature may serve the job if you do not have many transactions each time, less frequently, or due to a tight budget.