The double-entry account is the most used system to record accounting data, so it is split in two sides. Left hand side for debits and right hand side for credits. Depending on the type of account you may increase or decrease debits either increase or decrease credits. At the end of the account, you should sum them up and get two sided results, after you´ve subtracted one side from another, you´ll have the total amount of assets, liabilities or equities.
Assets accounts increase on the debit side and decreases on the right credit side. Liabilities accounts increase on the credit side and decreases on the debit side. The accounts of revenue, retained earnings and common stock (belong to owner´s equity) increase on the credit side. The accounts of dividends and expenses increase on the debit side. For example, if we do a business transaction and we earned money, then our cash account increases on the debit side. If we pay out money, our amount of cash decreases so the credit side. Otherwise, if we have expenses due to plant asset repairs we first debit expense account and credit cash (the particular plant asset should be adjusted too).
source: my notes and “financial accounting by horgren and harrison 6th edition”.