Exactly what accounts are affected by any given transaction is not a fixed thing. Just for example, in a simple accounting system you might have one account for "stock on hand". In a more complex system you might have this broken out into many accounts for different types of stock, stock in different locations, etc. So I can only suggest example specific accounts.
But account type -- asset, liability, capital (or "equity"), income, expense -- should be universal. Debit and credit rules should be universal.
1: Sold product on account:
You say it cost you $500 to produce. You don't say the selling price, but let's say it's, oh, $700.
Credit (decrease) Asset "Stock on hand" by $500. Debit (increase) Asset "Accounts receivable" by $700. Credit (increase) Income "Sales" by $700. Debit (increase) Expense "Cost of goods sold" by $500.
2: $1000 spent on wedding party by friend
I'm not sure how your friend's expenses affect your accounts. Are you asking how he would record this expense? Did you pay it for him? Are you expecting him to pay you back? Did he pay with cash, check, a credit card, bought on credit? I just don't know what's happening here.
But just for example, if you're asking how your friend would record this in his own records, and if he paid by check:
Credit (decrease) Asset "checking account" by $1000. Debit (increase) Expense "wedding expenses" by $1000.
If he paid with a credit card:
Credit (increase) Liability "credit card" by $1000. Debit (increase) Expense "wedding expenses" by $1000. When he pays off the credit card: Debit (decrease) Liability "credit card" by $1000. Credit (decrease) Asset "cash" by $1000. (Or more realistically, there are other expenses on the credit card and the amount would be higher.)
3: Issue $3000 in stock to partner company
I'm a little shakier on this, I haven't worked with the stock side of accounting. But here's my best stab:
Well, did you get anything in return? Like did they pay you for the stock? I wouldn't think you would just give someone stock as a present.
If they paid you cash for the stock:
Debit (increase) Asset "cash". Credit (decrease) Capital "shareholder equity".
Anyone else want to chime in on that one, I'm a little shaky there.
Here, let me give you the general rules. My boss years ago described it to me this way:
You only need to know three things to understand double-entry accounting:
1: There are five types of accounts: Assets: anything you have that has value, like cash, buildings, equipment, and merchandise. Includes things you may not actually have in your hands but that are rightly yours, like money people owe you but haven't yet paid. Liabilities: Anything you owe to someone else. Debts, merchandise paid for but not yet delivered, and taxes due. Capital (some call it "capital", others call it "equity"): The difference between Assets and Liabilities. The owners investment in the company, retained earnings, etc. Income: Money coming in, the biggest being sales. Expenses: Money going out, like salaries to employees, cost of purchasing merchandise for resale, rent, electric bill, taxes, etc.
Okay, that's a big "one thing".
2: Every transaction must update two or more accounts. Each update is either a "debit" or a "credit". The total of the debits must equal the total of the credits.
3: A dollar bill in your pocket is a debit.
With a little thought (okay, sometimes a lot of thought) you can figure out everything else from there.