How to reduce speed for specific devices on the network?

[Tejas01]

So I have Nokia G2425G-A GPON with Airtel. I wanted to share my wifi with some people but without affecting the security or giving them maximum speeds.
How can I ensure both? I was thinking that there would be a provision to enable guest account wherein I can determine the required speeds.
Is there another way where I can reduce speeds for them? They would be using wifi daily so it will be in my list.

 

[SVK]

With TP-Link Router I had tried that. It had option to create Guest Network and limit speed on Guest Network. I had created new Guest network and limited speed for that to 4 Mbps (I have 30 Mbps plan).
I wanted to test how it works, but my Router gone bad and had to reset.
Need to try that again from my side, how it works.

 

[venkatachar]

If your modem supports QoS/Traffic Shaping Rule, you can assign a static ip for the mac of particular device and use QoS to limit speed/access

 

[Sushubh]

Mac is useless to target devices. Both android and ios device now randomize Mac.