If you have any cash or held assets in your account, you will want to liquidate your M1 account.
If you have recurring deposits set up, you can cancel future scheduled deposits from Funding > Schedules.
We would advise against closing your account after liquidation. You will want to be able to sign in again next year to download tax documents. In addition, any earned dividends may still be paid to your account after your liquidation is completed.
If you never funded your M1 account and want to cancel, or have gotten all tax documents for a liquidated account, you can contact M1 Support with your M1 account email address to request to close the account. In your email, please make note of the account number you are requesting to close.