I changed my FB account to login, but someone still have access with my account

I can tell you what worked for me, what i did was this directly log someone else out of your Facebook account if they're already logged in on their device. However, you can remotely log out all active sessions, which will effectively log them out of any device except the one you're currently using. Here's how to do it:-

On the Facebook Website or Mobile App:-

1. Go to Settings (gear icon on desktop or menu icon with three lines on mobile).
2. Navigate to Security and Login (on desktop) or Settings & Privacy > Settings (on mobile).
3. Under the Security and Login section (desktop) or Password and Security (mobile), find Where You're Logged In.
4. Click See More to view all active sessions.
5. You'll see a list of devices where your account is currently logged in.
6. To log out of all devices except the one you're currently on, click Log Out of All Sessions at the bottom.
7. Confirm by clicking Log Out in the pop-up window.
This will log your account out of all other devices, including the one the other person might be using. More details instruction below.

https://www.youtube.com/watch?v=ACq2GxEEa24&ab_channel=TheGeekPage