I have trouble figuring out if this adjustment that says Professional Fees earned on August 31st but not recorded, $750. What I did was debit accounts receivable adjustments column and credited professional fees. I would like to know if this is correct or not?

Professional Fees eaned means that you provided services to a customer, but did not bill the customer yet.

Your journal entry will be:
Debit Accounts Receivable for the amount
Credit Professional Fees Earned for the amount.

Adjusting entries are for one Balance sheet account and one Income Statement account