Can you please let me know what my non renewal of lease to my apts should contain? Thank you.

Probably just say "I will not be renewing my lease, and as such my date to vacate the unit is ____" just keep it simple and direct. Make sure the landlord gets it, ideally by signing for it, and keep a copy for yourself with a handwritten date of delivery in case there are problems.

Are you not going to renew any leases in the entire apartment ?

But normally formally to them, name, address apartment number, you would note the lease date and date the lease ends and inform them that you will no longer be renewing the lease.