Can I send a legal notice for loan repayment since 6 month ?

In response to your inquiry and please note that If you gave a loan for one month and six months have passed without payment you should first send a legal notice demanding repayment within 7 to 14 days. If he still does not pay you can file a civil suit for recovery of the amount. If you have written proof bank record, or messages admitting the loan, your case will be stronger. Limitation period is 3 years from the date of default. A criminal case is possible only if you can prove he had dishonest intention from the beginning; otherwise, it remains a civil matter. Proper course: Legal notice first, then recovery suit.