how to turn off apple track pad...battery model

For the one with removable batteries. press and hold the power button (right end of "tube" opposite the battery compartment) until a green light flashes, then release the button.

Manual: https://manuals.info.apple.com/MANUALS/1000/MA1544/en_US/Magic_Trackpad_UG.pdf

On those models they did not have an on/off switch.

the Magic Trackpad 1 (A1339) sitting in front of me has a very proper power button camouflaged as the right end-cap. Works fine.

From the manual:

On those models they did not have an on/off switch. On mine I simply unscrewed the battery cap until it turn off and then screwed the cap back in. To turn it back on simply depress the cap and you should see the green light come on indicating it has power. Then wait for it to pair with the computer.

When I had mine, the switch worked fine to turn it on, it never turned it off though. As I rarely turned it off, I just learned the process I mentioned and lived with it for years. My MTP 2 has the rechargeable batteries and I like that design much more than the original.

All of Apple track pads have batteries, some batteries are not replaceable but rechargeable the earlier ones used replaceable batteries. Which model do you have?????????????