How do I report receivables on its classified balance sheet?
Allowances for uncollectible accounts
Cash
Accounts receivable
Accounts payable
Salaries revenue
Other assets
Cost of goods sold and other expenses
Notes payable

Assets and expenses are debits
Liabilities and Revenues are credits

For a classified Balance Sheet, you need to separate out the types of assets you have. Current assets are those that will be received or used within on year. As a general rule, Accounts Receivables are collected within one year and so therefore are current.

The Allowance for Doubtful Accounts is a contra asset which offsets the balance in the Accounts Receivable. It's still a current asset (since it belongs with the A/R), but it's a credit balance so that it subtracts from the receivables. If all the receivables won't be collected, then they aren't worth as much, so we use the allowance account to offset the balance of receivables, by an amount estimated as being uncollectible.