Secure Folder comes pre-installed in Samsung premium series but Samsung low budget series phones are not not having Secure Folder. Secure Folder is missing in M-Series Samsung smartphones.
You can enable Samsung Secure Folder in Samsung phones easily. Navigate to the location Settings > Lock screen and security > Secure Folder and enable it.
But you can still install Secure Folder in Samsung M-Series phones also.
Samsung S-Secure works similar to Secure Folder that comes pre-installed in most of the Samsung devices with defense grade KNOX security.
But still you can Hide and lock apps in Samsung phone using Secure app, You can also hide photos, videos, documents and other files using S-Secure app.
The main drawback of manually installing S-secure app is that if anyone who has access to your smartphone can easily uninstall S-Secure app. As soon as S-secure app is uninstalled from your Samsung mobile your all hidden and locked apps will be visible to everyone.