If you mean the display resolution of your TV, there's no way, because the resolution of a TV is fixed. And TCL Roku TV has 4K Roku TV and 1080P Roku TV, depending on your TV's model. But you can change the output resolution.
If you want to change the input resolution, for example, if you connect your TCL 4K Roku TV to your PS4, and you want the PS4 to play in 4K, you need some settings.
1. On the Home screen of your TV, select
Settings with your remote.
2. Select
TV Inputs in Settings, you can see the input options, and select the input that your PS4 or other device is connected to.
3. Select go to
HDMI Mode, and choose
HDMI 2.0 for your PS4.
Now you can select the output resolution.
4. Back to the
Home screen and choose
Settings.
5. Go to
Sound and Screen and then
Video Output Settings.
6. You can now select either 2160p- YUV420 or 2160p- RGB in the
Resolution menu.