@vikushgupta we really need to know exactly what you mean by slow. The user interface on this model has been reported as being sluggish and lagging (especially after and update). There are a few things you could try. You want to start off by closing ALL background apps and then force restart your phone.
* Tap the Recent apps key to view the applications that run in the background.
* Tap Close all to force stop all of them.
* Now press and hold the Volume Down button and the power key for 8 seconds. Your phone will shut down and power back up.
* Once the Samsung logo shows, release both keys and allow the device to continue the boot process.
You also would want to Clear cache. To do that, go to Settings > Storage > Cached data, and tap on "Clear cache".
If that still does not resolve the issues, try to start your Samsung phone in Safe mode and see if that changes anything. If so, it is possible one of your Apps that is causing this. To get into safe mode check the [https://www.samsung.com/in/support/mobile-devices/safe-mode-on-samsung-phones/|Samsung site] for instructions.
The last thing would be a Factory reset. remember that this WILL delete all of your data, so be sure to back up your important files before doing that. To perform a factory reset, go to Settings > General management > Reset > Factory data reset.