change the password
Open the Instagram app on your mobile phone.
Go to the Profile tab at the bottom right.
Now select the menu in the top right corner and tap on ‘Settings’.
Go to ‘Security’ in Settings.
Here the first option is ‘Password’, select it.
Now enter your current password as well as the new password twice.
Once the process is complete, hit the ‘checkmark’ button in the top right. Your work is done.
exit active session
Open the Instagram app on your mobile.
Tap on your profile tab in the lower right corner.
Now select the menu (3 line) in the upper right corner.
From here go to Settings. and select Security.
Now tap on ‘Login Activity’.
From here you can see all the devices on which your account is logged in.
To protect your account from hackers, remove any unrecognized devices from there. Read this also- Why there is a problem in setting up 5G network even in 5G ready mobile phones, what is the solution?